Question 1

Which of the following statements best describes the octet rule?

Accepted Answer

Atoms tend to gain, lose, or share electrons to achieve eight electrons in their valence shell.

Question 2

How many valence electrons does a sulfur (S) atom have?

Accepted Answer

$$6$$

Question 3

Which of the following ions is isoelectronic with neon ($$Ne$$)?

Accepted Answer

$$F^-$$

Question 4

What is the correct formula for the ionic compound formed between aluminum and oxygen?

Accepted Answer

$$Al_2O_3$$

Question 5

Which of the following best describes the bonding in a molecule of $$Cl_2$$?

Accepted Answer

A single covalent bond formed by sharing one pair of electrons.

Question 6

What is the name of the compound $$N_2O_4$$?

Accepted Answer

Dinitrogen tetroxide

Question 7

Calculate the molar mass of $$MgSO_4 ($$magnesium sulfate).

Accepted Answer

$$120.37\ \mathrm{g/mol}$$

Question 8

How many molecules are present in $$5.01$$ grams of $$MgSO_4$$? (Molar mass $$= 120.37\ \mathrm{g/mol}$$, Avogadro's number $$= 6.022 	imes 10$$^{23}$$)

Accepted Answer

$$2.51 	imes 10$$^{22}$$

Question 9

Which of the following molecules is nonpolar, despite containing polar bonds?

Accepted Answer

$$CO_2$$

Question 10

What is the molecular geometry of methane ($$CH_4) $$according to VSEPR theory?

Accepted Answer

Tetrahedral

Question 11

Which of the following best explains why water ($$H_2O) is a $$polar molecule?

Accepted Answer

It has a bent shape and polar bonds, resulting in an uneven distribution of electrons.

Question 12

Which of the following elements has the highest electronegativity?

Accepted Answer

Fluorine

Question 13

What is the correct name for $$Fe(NO_3$)_2$$?

Accepted Answer

Iron(II) nitrate

Question 14

Which of the following compounds contains both ionic and covalent bonds?

Accepted Answer

$$CaCO_3$$

Question 15

A sample contains $$3.01 	imes 10$$^{23}$$ molecules of glucose (C_6H$$_{12}$$O_6). $$How many moles of glucose are present?

Accepted Answer

$$0.5$$ moles

Question 16

Which of the following best describes the bond in $$HCl$$?

Accepted Answer

A polar covalent bond, with electrons more attracted to Cl.

Question 17

Which of the following is the correct Lewis structure for carbon dioxide ($$CO_2$$)?

Accepted Answer

$$O=C=O$$

Question 18

What is the charge on the ion formed by magnesium?

Accepted Answer

$$2+$$

Question 19

Which of the following best describes the difference between ionic and covalent compounds?

Accepted Answer

Ionic compounds are formed by electron transfer between metals and nonmetals; covalent compounds are formed by electron sharing between nonmetals.

Question 20

Which of the following molecules has a trigonal planar geometry?

Accepted Answer

$$BF_3$$

Chapter 3: Compounds—How Elements Combine (GOB Chemistry Study Guide)

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