Content check — Chemistry: Atoms First, Chapter 3: Electronic Structure and Periodic Properties of Elements

Every problem in the chapter beside the book’s answer, a chapter at a time as you scroll.

Chapter 3: Electronic Structure and Periodic Properties of Elements

69 problems · 8 figures

Example 3.1 §3.1 source ↗

One of the frequencies used to transmit and receive cellular telephone signals in the United States is 850 MHz. What is the wavelength in meters of these radio waves?

Answer

0.353 m = 35.3 cm

Example 3.2 §3.1 source ↗

The microwaves in an oven are of a specific frequency that will heat the water molecules contained in food. (This is why most plastics and glass do not become hot in a microwave oven-they do not contain water molecules.) This frequency is about 3

\times

10⁹ Hz. What is the energy of one photon in these microwaves?

Answer

\times

10⁻²⁴ J

Example 3.3 §3.1 source ↗

Calculate the threshold energy in kJ/mol of electrons in aluminum, given that the lowest frequency photon for which the photoelectric effect is observed is 9.87

\times

10¹⁴ Hz.

Answer

394

Example 3.4 §3.2 source ↗

The electron in Figure 3.15 is promoted even further to an orbit with n = 6. What is its new energy?

The figure includes a diagram representing the relative energy levels of the quantum numbers of the hydrogen atom. An upward pointing arrow at the left of the diagram is labeled, “E.” A grey shaded vertically oriented rectangle is placed just right of the arrow. The rectangle height matches the arrow length. Colored, horizontal line segments are placed inside the rectangle and labels are placed to the right of the box, arranged in a column with the heading, “Energy, n.” At the very base of the rectangle, a purple horizontal line segment is drawn. A black line extends to the right to the label, “1.” At a level approximately three-quarters of the distance to the top of the rectangle, a blue horizontal line segment is drawn. A black line extends to the right to the label, “2.” At a level approximately seven-eighths the distance from the base of the rectangle, a green horizontal line segment is drawn. A black line extends to the right to the label, “3.” Just a short distance above this segment, an orange horizontal line segment is drawn. A black line segment extends to the right to the label, “4.” Just above this segment, a red horizontal line segment is drawn. A black line extends to the right to the label, “5.” Just a short distance above this segment, a brown horizontal line segment is drawn. A black line extends to the right to the label, “infinity.” Arrows are drawn to depict energies of photons absorbed, as shown by upward pointing arrows on the left, or released as shown by downward pointing arrows on the right side of the diagram between the colored line segments. The label, “Electron moves to higher energy as light is absorbed,” is placed beneath the upward pointing arrows. Similarly, the label, “Electron moves to lower energy as light is emitted,” appears beneath the downward pointing arrows. Moving left to right across the diagram, arrows extend from one colored line segment to the next in the following order: purple to blue, purple to green, purple to orange, purple to red, purple to brown, blue to green, blue to orange, and blue to red. The arrows originating from the same colored segment are grouped together by close placement of the arrows. Similarly, the downward arrows follow in this sequence; brown to purple, red to purple, orange to purple, green to purple, blue to purple, red to blue, orange to blue, and green to blue. Arrows are again grouped by close placement according to the color at which the arrows end. — Figure 3.15 in the book ↗

Answer

−6.053

\times

10^–20 J

Example 3.5 §3.2 source ↗

What is the energy in joules and the wavelength in meters of the photon produced when an electron falls from the n = 5 to the n = 3 level in a He⁺ ion (Z = 2 for He⁺)?

Answer

6.198

\times

10^–19 J; 3.205

\times

10⁻⁷ m

Example 3.6 §3.3 source ↗

Calculate the wavelength of a softball with a mass of 100 g traveling at a velocity of 35 m s^–1, assuming that it can be modeled as a single particle.

Answer

1.9 $\times$ 10^–34 m.

We never think of a thrown softball having a wavelength, since this wavelength is so small it is impossible for our senses or any known instrument to detect. Since de Broglie wavelength is inversely proportional to both particle mass and velocity, the particle’s momentum (mathematical product of mass and velocity) must be sufficiently small to yield a detectably large wavelength.

Example 3.7 §3.3 source ↗

Identify the subshell in which electrons with the following quantum numbers are found: (a) n = 3, l = 1; (b) n = 5, l = 3; (c) n = 2, l = 0.

Answer

(a) 3p (b) 5f (c) 2s

Example 3.8 §3.3 source ↗

If a shell contains a maximum of 32 electrons, what is the principal quantum number, n?

Answer

n = 4

Example 3.9 §3.3 source ↗

How many orbitals have l = 2 and n = 3?

Answer

The five degenerate 3d orbitals

Example 3.10 §3.4 source ↗

Identify the atoms from the electron configurations given:

(a) [Ar]4s²3d⁵

(b) [Kr]5s²4d¹⁰5p⁶

Answer

(a) Mn (b) Xe

Example 3.11 §3.4 source ↗

Which ion with a +2 charge has the electron configuration 1s²2s²2p⁶3s²3p⁶4s²3d¹⁰4p⁶4d⁵? Which ion with a +3 charge has this configuration?

Answer

Tc²⁺, Ru³⁺

Example 3.12 §3.5 source ↗

Give an example of an atom whose size is smaller than fluorine.

Answer

Ne or He

Example 3.13 §3.5 source ↗

Which has the lowest value for IE₁: O, Po, Pb, or Ba?

Answer

Example 3.14 §3.6 source ↗

Give the group name for each of the following elements:

(a) krypton

(b) selenium

(d) lithium

Answer

(a) noble gas; (b) chalcogen; (c) alkaline earth metal; (d) alkali metal

Example 3.15 §3.7 source ↗

Give the symbol and name for the ion with 34 protons and 36 electrons.

Answer

Se²⁻, the selenide ion

Example 3.16 §3.7 source ↗

Aluminum and carbon react to form an ionic compound. Predict which forms an anion, which forms a cation, and the charges of each ion. Write the symbol for each ion and name them.

Answer

Al will form a cation with a charge of 3+: Al³⁺, an aluminum ion. Carbon will form an anion with a charge of 4−: C⁴⁻, a carbide ion.

Example 3.17 §3.7 source ↗

Predict the formula of the ionic compound formed between the sodium cation, Na⁺, and the sulfide anion, S²⁻.

Answer

Na₂S

Example 3.18 §3.7 source ↗

Predict the formula of the ionic compound formed between the lithium ion and the peroxide ion,

O_{2}^{2-}

(Hint: Use the periodic table to predict the sign and the charge on the lithium ion.)

Answer

Li₂O₂

Example 3.19 §3.7 source ↗

Using the periodic table, predict whether the following compounds are ionic or covalent:

(a) SO₂

(b) CaF₂

(d) Al₂(SO₄)₃

Answer

(a) molecular; (b) ionic; (c) molecular; (d) ionic

3-1 §3.1 source ↗

The light produced by a red neon sign is due to the emission of light by excited neon atoms. Qualitatively describe the spectrum produced by passing light from a neon lamp through a prism.

Answer

The spectrum consists of colored lines, at least one of which (probably the brightest) is red.

3-3 §3.1 source ↗

FM-95, an FM radio station, broadcasts at a frequency of 9.51

\times

10⁷ s⁻¹ (95.1 MHz). What is the wavelength of these radio waves in meters?

Answer

3.15 m

3-5 §3.1 source ↗

Light with a wavelength of 614.5 nm looks orange. What is the energy, in joules, per photon of this orange light? What is the energy in eV (1 eV = 1.602

\times

10⁻¹⁹ J)?

Answer

3.233

\times

10⁻¹⁹ J; 2.018 eV

3-7 §3.1 source ↗

A photon of light produced by a surgical laser has an energy of 3.027

\times

10⁻¹⁹ J. Calculate the frequency and wavelength of the photon. What is the total energy in 1 mole of photons? What is the color of the emitted light?

Answer

ν = 4.568

\times

10¹⁴ s⁻¹; λ = 656.3 nm; Energy mol⁻¹ = 1.823

\times

10⁵ J mol⁻¹; red

3-9 §3.1 source ↗

The emission spectrum of cesium contains two lines whose frequencies are (a) 3.45

\times

10¹⁴ Hz and (b) 6.53

\times

10¹⁴ Hz. What are the wavelengths and energies per photon of the two lines? What color are the lines?

Answer

(a) λ = 8.69

\times

10⁻⁷ m; E = 2.29

\times

10⁻¹⁹ J; (b) λ = 4.59

\times

10⁻⁷ m; E = 4.33

\times

10⁻¹⁹ J; The color of (a) is red; (b) is blue.

3-11 §3.1 source ↗

One of the radiographic devices used in a dentist's office emits an X-ray of wavelength 2.090

\times

10⁻¹¹ m. What is the energy, in joules, and frequency of this X-ray?

Answer

E = 9.502

\times

10⁻¹⁵ J; ν = 1.434

\times

10¹⁹ s⁻¹

3-13 §3.1 source ↗

RGB color television and computer displays use cathode ray tubes that produce colors by mixing red, green, and blue light. If we look at the screen with a magnifying glass, we can see individual dots turn on and off as the colors change. Using a spectrum of visible light, determine the approximate wavelength of each of these colors. What is the frequency and energy of a photon of each of these colors?

Answer

Red: 660 nm; 4.54

\times

10¹⁴ Hz; 3.01

\times

10⁻¹⁹ J. Green: 520 nm; 5.77

\times

10¹⁴ Hz; 3.82

\times

10⁻¹⁹ J. Blue: 440 nm; 6.81

\times

10¹⁴ Hz; 4.51

\times

10⁻¹⁹ J. Somewhat different numbers are also possible.

3-15 §3.1 source ↗

What is the threshold frequency for sodium metal if a photon with frequency 6.66

\times

10¹⁴ s⁻¹ ejects an electron with 7.74

\times

10⁻²⁰ J kinetic energy? Will the photoelectric effect be observed if sodium is exposed to orange light?

Answer

5.49

\times

10¹⁴ s⁻¹; no

3-17 §3.2 source ↗

What does it mean to say that the energy of the electrons in an atom is quantized?

Answer

Quantized energy means that the electrons can possess only certain discrete energy values; values between those quantized values are not permitted.

3-19 §3.2 source ↗

The electron volt (eV) is a convenient unit of energy for expressing atomic-scale energies. It is the amount of energy that an electron gains when subjected to a potential of 1 volt; 1 eV = 1.602

\times

10^–19 J. Using the Bohr model, determine the energy, in electron volts, of the photon produced when an electron in a hydrogen atom moves from the orbit with n = 5 to the orbit with n = 2. Show your calculations.

Answer

2.856 eV

3-21 §3.2 source ↗

Using the Bohr model, determine the lowest possible energy for the electron in the He⁺ ion.

Answer

−8.716

\times

10⁻¹⁸ J

3-23 §3.2 source ↗

Using the Bohr model, determine the energy of an electron with n = 8 in a hydrogen atom.

Answer

−3.405

\times

10⁻²⁰ J

3-25 §3.2 source ↗

What is the radius, in angstroms, of the orbital of an electron with n = 8 in a hydrogen atom?

Answer

33.9 Å

3-27 §3.2 source ↗

Using the Bohr model, determine the energy in joules of the photon produced when an electron in a Li²⁺ ion moves from the orbit with n = 2 to the orbit with n = 1.

Answer

1.471

\times

10⁻¹⁷ J

3-29 §3.2 source ↗

How are the Bohr model and the Rutherford model of the atom similar? How are they different?

Answer

Both involve a relatively heavy nucleus with electrons moving around it, although strictly speaking, the Bohr model works only for one-electron atoms or ions. According to classical mechanics, the Rutherford model predicts a miniature “solar system” with electrons moving about the nucleus in circular or elliptical orbits that are confined to planes. If the requirements of classical electromagnetic theory that electrons in such orbits would emit electromagnetic radiation are ignored, such atoms would be stable, having constant energy and angular momentum, but would not emit any visible light (contrary to observation). If classical electromagnetic theory is applied, then the Rutherford atom would emit electromagnetic radiation of continually increasing frequency (contrary to the observed discrete spectra), thereby losing energy until the atom collapsed in an absurdly short time (contrary to the observed long-term stability of atoms). The Bohr model retains the classical mechanics view of circular orbits confined to planes having constant energy and angular momentum, but restricts these to quantized values dependent on a single quantum number, n. The orbiting electron in Bohr’s model is assumed not to emit any electromagnetic radiation while moving about the nucleus in its stationary orbits, but the atom can emit or absorb electromagnetic radiation when the electron changes from one orbit to another. Because of the quantized orbits, such “quantum jumps” will produce discrete spectra, in agreement with observations.

3-31 §3.3 source ↗

How are the Bohr model and the quantum mechanical model of the hydrogen atom similar? How are they different?

Answer

Both models have a central positively charged nucleus with electrons moving about the nucleus in accordance with the Coulomb electrostatic potential. The Bohr model assumes that the electrons move in circular orbits that have quantized energies, angular momentum, and radii that are specified by a single quantum number, n = 1, 2, 3, …, but this quantization is an ad hoc assumption made by Bohr to incorporate quantization into an essentially classical mechanics description of the atom. Bohr also assumed that electrons orbiting the nucleus normally do not emit or absorb electromagnetic radiation, but do so when the electron switches to a different orbit. In the quantum mechanical model, the electrons do not move in precise orbits (such orbits violate the Heisenberg uncertainty principle) and, instead, a probabilistic interpretation of the electron’s position at any given instant is used, with a mathematical function ψ called a wavefunction that can be used to determine the electron’s spatial probability distribution. These wavefunctions, or orbitals, are three-dimensional stationary waves that can be specified by three quantum numbers that arise naturally from their underlying mathematics (no ad hoc assumptions required): the principal quantum number, n (the same one used by Bohr), which specifies shells such that orbitals having the same n all have the same energy and approximately the same spatial extent; the angular momentum quantum number l, which is a measure of the orbital’s angular momentum and corresponds to the orbitals’ general shapes, as well as specifying subshells such that orbitals having the same l (and n) all have the same energy; and the orientation quantum number m, which is a measure of the z component of the angular momentum and corresponds to the orientations of the orbitals. The Bohr model gives the same expression for the energy as the quantum mechanical expression and, hence, both properly account for hydrogen’s discrete spectrum (an example of getting the right answers for the wrong reasons, something that many chemistry students can sympathize with), but gives the wrong expression for the angular momentum (Bohr orbits necessarily all have non-zero angular momentum, but some quantum orbitals [s orbitals] can have zero angular momentum).

3-33 §3.3 source ↗

Describe the properties of an electron associated with each of the following four quantum numbers: n, l, m_l, and m_s.

Answer

n determines the general range for the value of energy and the probable distances that the electron can be from the nucleus. l determines the shape of the orbital. m₁ determines the orientation of the orbitals of the same l value with respect to one another. m_s determines the spin of an electron.

3-35 §3.3 source ↗

Identify the subshell in which electrons with the following quantum numbers are found:

(a) n = 2, l = 1

(b) n = 4, l = 2

Answer

(a) 2p; (b) 4d; (c) 6s

3-37 §3.3 source ↗

Identify the subshell in which electrons with the following quantum numbers are found:

(a) n = 3, l = 2

(b) n = 1, l = 0

Answer

(a) 3d; (b) 1s; (c) 4f

3-39 §3.3 source ↗

Sketch the boundary surface of a

d_{x^{2} − y^{2}}

and a p_y orbital. Be sure to show and label the axes.

Answer

This figure contains two diagrams. The first is of a 2 p subscript y orbital. The second is of a d subscript x squared minus y squared orbital. The first diagram has two spherical shapes joined at the origin when oriented along the y axis on an x y and z coordinate plane. The second diagram shows four ellipsoid lobes with ends centered around the origin. Two of these ellipsoid lobes are oriented along the x axis and two are oriented along the y axis on the x y and z coordinate plane.

3-41 §3.3 source ↗

Consider the orbitals shown here in outline.

This figure contains three diagrams. In x, a circle is drawn with a dot at the center. In y, two nearly ellipsoid shapes are oriented horizontally with a dot between them. In z, four shapes like those in y are oriented in an x shape with a dot at the center.

(a) What is the maximum number of electrons contained in an orbital of type (x)? Of type (y)? Of type (z)?

(b) How many orbitals of type (x) are found in a shell with n = 2? How many of type (y)? How many of type (z)?

(c) Write a set of quantum numbers for an electron in an orbital of type (x) in a shell with n = 4. Of an orbital of type (y) in a shell with n = 2. Of an orbital of type (z) in a shell with n = 3.

(d) What is the smallest possible n value for an orbital of type (x)? Of type (y)? Of type (z)?

(e) What are the possible l and m_l values for an orbital of type (x)? Of type (y)? Of type (z)?

Answer

(a) x. 2, y. 2, z. 2; (b) x. 1, y. 3, z. 0; (c) x. 4 0 0

\frac{1}{2},

y. 2 1 0

\frac{1}{2},

z. 3 2 0

\frac{1}{2};

(d) x. 1, y. 2, z. 3; (e) x. l = 0, m_l = 0, y. l = 1, m_l = –1, 0, or +1, z. l = 2, m_l = –2, –1, 0, +1, +2

3-43 §3.3 source ↗

How many electrons could be held in the second shell of an atom if the spin quantum number m_s could have three values instead of just two? (Hint: Consider the Pauli exclusion principle.)

Answer

3-45 §3.3 source ↗

Write a set of quantum numbers for each of the electrons with an n of 4 in a Se atom.

Answer

n	l	m_l	s
4	0	0	$+ \frac{1}{2}$
4	0	0	$- \frac{1}{2}$
4	1	−1	$+ \frac{1}{2}$
4	1	0	$+ \frac{1}{2}$
4	1	+1	$+ \frac{1}{2}$
4	1	−1	$- \frac{1}{2}$

3-47 §3.4 source ↗

Read the labels of several commercial products and identify monatomic ions of at least six main group elements contained in the products. Write the complete electron configurations of these cations and anions.

Answer

For example, Na⁺: 1s²2s²2p⁶; Ca²⁺: 1s²2s²2p⁶3s²3p⁶; Sn²⁺: 1s²2s²2p⁶3s²3p⁶3d¹⁰4s²4p⁶4d¹⁰5s²; F^–: 1s²2s²2p⁶; O^2–: 1s²2s²2p⁶; Cl^–: 1s²2s²2p⁶3s²3p⁶.

3-49 §3.4 source ↗

Using complete subshell notation (1s²2s²2p⁶, and so forth), predict the electron configuration of each of the following atoms:

(a) N

(b) Si

(d) Te

(e) Tb

Answer

(a) 1s²2s²2p³; (b) 1s²2s²2p⁶3s²3p²; (c) 1s²2s²2p⁶3s²3p⁶4s²3d⁶; (d) 1s²2s²2p⁶3s²3p⁶4s²3d¹⁰4p⁶5s²4d¹⁰5p⁴; (e) 1s²2s²2p⁶3s²3p⁶4s²3d¹⁰4p⁶5s²4d¹⁰5p⁶6s²4f⁹

3-51 §3.4 source ↗

What additional information do we need to answer the question “Which ion has the electron configuration 1s²2s²2p⁶3s²3p⁶”?

Answer

The charge on the ion.

3-53 §3.4 source ↗

Use an orbital diagram to describe the electron configuration of the valence shell of each of the following atoms:

(a) N

(b) Si

(d) Te

(e) Mo

Answer

(a)

(b)

(c)

(d)

(e)

3-55 §3.4 source ↗

Which atom has the electron configuration 1s²2s²2p⁶3s²3p⁶4s²3d¹⁰4p⁶5s²4d²?

Answer

3-57 §3.4 source ↗

Which ion with a +1 charge has the electron configuration 1s²2s²2p⁶3s²3p⁶3d¹⁰4s²4p⁶? Which ion with a –2 charge has this configuration?

Answer

Rb⁺, Se²⁻

3-59 §3.4 source ↗

Which of the following has two unpaired electrons?

(a) Mg

(b) Si

(d) Both Mg and S

(e) Both Si and S.

Answer

Although both (b) and (c) are correct, (e) encompasses both and is the best answer.

3-61 §3.4 source ↗

Which atom would be expected to have a half-filled 4s subshell?

Answer

3-63 §3.4 source ↗

Thallium was used as a poison in the Agatha Christie mystery story “The Pale Horse.” Thallium has two possible cationic forms, +1 and +3. The +1 compounds are the more stable. Write the electron structure of the +1 cation of thallium.

Answer

1s²2s²2p⁶3s²3p⁶4s²3d¹⁰4p⁶5s²4d¹⁰5p⁶6s²4f¹⁴5d¹⁰

3-65 §3.4 source ↗

Cobalt–60 and iodine–131 are radioactive isotopes commonly used in nuclear medicine. How many protons, neutrons, and electrons are in atoms of these isotopes? Write the complete electron configuration for each isotope.

Answer

Co has 27 protons, 27 electrons, and 33 neutrons: 1s²2s²2p⁶3s²3p⁶4s²3d⁷. I has 53 protons, 53 electrons, and 78 neutrons: 1s²2s²2p⁶3s²3p⁶3d¹⁰4s²4p⁶4d¹⁰5s²5p⁵.

3-67 §3.5 source ↗

Based on their positions in the periodic table, predict which has the smallest atomic radius: Mg, Sr, Si, Cl, I.

Answer

3-69 §3.5 source ↗

Based on their positions in the periodic table, predict which has the largest first ionization energy: Mg, Ba, B, O, Te.

Answer

3-71 §3.5 source ↗

Based on their positions in the periodic table, rank the following atoms in order of increasing first ionization energy: F, Li, N, Rb

Answer

Rb < Li < N < F

3-73 §3.5 source ↗

Atoms of which group in the periodic table have a valence shell electron configuration of ns²np³?

Answer

15 (5A)

3-75 §3.5 source ↗

Based on their positions in the periodic table, list the following atoms in order of increasing radius: Mg, Ca, Rb, Cs.

Answer

Mg < Ca < Rb < Cs

3-77 §3.5 source ↗

Based on their positions in the periodic table, list the following ions in order of increasing radius: K⁺, Ca²⁺, Al³⁺, Si⁴⁺.

Answer

Si⁴⁺ < Al³⁺ < Ca²⁺ < K⁺

3-79 §3.5 source ↗

Which atom and/or ion is (are) isoelectronic with Br⁺: Se²⁺, Se, As^–, Kr, Ga³⁺, Cl^–?

Answer

Se, As⁻

3-81 §3.5 source ↗

Compare both the numbers of protons and electrons present in each to rank the following ions in order of increasing radius: As^3–, Br^–, K⁺, Mg²⁺.

Answer

Mg²⁺ < K⁺ < Br^– < As^3–

3-83 §3.5 source ↗

Of the five elements Sn, Si, Sb, O, Te, which has the most endothermic reaction? (E represents an atom.) What name is given to the energy for the reaction?

E (g) ⟶

E^{+} (g) +

e^{-}

Answer

O, IE₁

3-85 §3.5 source ↗

Which main group atom would be expected to have the lowest second ionization energy?

Answer

3-87 §3.6 source ↗

Using the periodic table, classify each of the following elements as a metal or a nonmetal, and then further classify each as a main-group (representative) element, transition metal, or inner transition metal:

(a) uranium

(b) bromine

(d) neon

(e) gold

(f) americium

(g) rhodium

(h) sulfur

(i) carbon

(j) potassium

Answer

(a) metal, inner transition metal; (b) nonmetal, representative element; (c) metal, representative element; (d) nonmetal, representative element; (e) metal, transition metal; (f) metal, inner transition metal; (g) metal, transition metal; (h) nonmetal, representative element; (i) nonmetal, representative element; (j) metal, representative element

3-89 §3.6 source ↗

Using the periodic table, identify the lightest member of each of the following groups:

(a) noble gases

(b) alkaline earth metals

(d) chalcogens

Answer

(a) He; (b) Be; (c) Li; (d) O

3-91 §3.6 source ↗

Use the periodic table to give the name and symbol for each of the following elements:

(a) the noble gas in the same period as germanium

(b) the alkaline earth metal in the same period as selenium

(d) the chalcogen in the same period as cadmium

Answer

(a) krypton, Kr; (b) calcium, Ca; (c) fluorine, F; (d) tellurium, Te

3-93 §3.6 source ↗

Write a symbol for each of the following neutral isotopes. Include the atomic number and mass number for each.

(a) the alkali metal with 11 protons and a mass number of 23

(b) the noble gas element with 75 neutrons in its nucleus and 54 electrons in the neutral atom

(d) the alkaline earth metal with 88 electrons and 138 neutrons

Answer

(a)

_{11}^{23} Na

; (b)

_{54}^{129} Xe

; (c)

_{33}^{73} As

; (d)

_{88}^{226} Ra

3-95 §3.7 source ↗

Using the periodic table, predict whether the following chlorides are ionic or covalent: KCl, NCl₃, ICl, MgCl₂, PCl₅, and CCl₄.

Answer

Ionic: KCl, MgCl₂; Covalent: NCl₃, ICl, PCl₅, CCl₄

3-97 §3.7 source ↗

For each of the following compounds, state whether it is ionic or covalent. If it is ionic, write the symbols for the ions involved:

(a) NF₃

(b) BaO,

(d) Sr(H₂PO₄)₂

(e) IBr

(f) Na₂O

Answer

(a) covalent; (b) ionic, Ba²⁺, O²⁻; (c) ionic,

{NH}_{4}^{+},

{CO}_{3}^{2−};

(d) ionic, Sr²⁺,

H_{2} {PO}_{4}^{-};

(e) covalent; (f) ionic, Na⁺, O²⁻

3-99 §3.7 source ↗

For each of the following pairs of ions, write the symbol for the formula of the compound they will form.

(a) Ca²⁺, S²⁻

(b) ${NH}_{4}^{+},$ ${SO}_{4}^{2−}$

(d) Na⁺, ${HPO}_{4}^{2−}$

(e) Mg²⁺, ${PO}_{4}^{3−}$

Answer

(a) CaS; (b) (NH₄)₂SO₄; (c) AlBr₃; (d) Na₂HPO₄; (e) Mg₃ (PO₄)₂

Loading chapter 4…

Problems and answers are adapted from Chemistry: Atoms First 2e by Paul Flowers, Edward J. Neth, William R. Robinson, Klaus Theopold and Richard Langley, OpenStax, and are used under the CC BY-NC-SA 4.0 licence. Access for free at https://openstax.org/books/chemistry-atoms-first-2e/pages/1-introduction. Illustrations: Copyright Rice University, OpenStax, under CC BY-NC-SA 4.0 license. This adaptation is released under the same licence, is non-commercial, and is neither affiliated with nor endorsed by OpenStax or Rice University.