$Z_{\text{eff}}$ increases across a period due to increased nuclear charge and poor shielding by valence electrons.

Question 1

Which of the following elements has the largest atomic radius?

Accepted Answer

K

Question 2

Which of the following ions is isoelectronic with Ne and has the smallest radius?

Accepted Answer

Na\^\+

Question 3

Which of the following statements about ionization energy is correct?

Accepted Answer

Ionization energy decreases down a group and increases across a period.

Question 4

Which of the following electron configurations represents a paramagnetic atom?

Accepted Answer

$1s^2\ 2s^2\ 2p^3$

Question 5

Which of the following best explains why the second ionization energy of sodium is much greater than the first?

Accepted Answer

The second electron is removed from a noble gas core, which is much more stable.

Question 6

Which of the following compounds is named correctly?

Accepted Answer

Na\_2SO\_4: sodium sulfate

Question 7

A sample of a compound contains 12.0 g of carbon and 32.0 g of oxygen. What is the empirical formula of the compound?

Accepted Answer

CO\_2

Question 8

Which of the following is a correct Lewis structure for the nitrate ion, NO\_3\^-?

Accepted Answer

N is double-bonded to one O and single-bonded to two O atoms, with resonance among the O atoms.

Question 9

Which of the following elements is a transition metal?

Accepted Answer

Fe

Question 10

How many moles of water are present in 36.0 g of H\_2O? (Molar mass of H\_2O = 18.0 g/mol)

Accepted Answer

$2.0\ 	ext{mol}$

Question 11

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

Accepted Answer

Ionic bonds involve the transfer of electrons; covalent bonds involve the sharing of electrons.

Question 12

Which of the following is the correct electron configuration for the Fe\^{2+} ion?

Accepted Answer

$[Ar]\ 3d^6$

Question 13

A compound is found to contain 40.0% C, 6.7% H, and 53.3% O by mass. What is its empirical formula?

Accepted Answer

CH\_2O

Question 14

Which of the following statements about effective nuclear charge ($Z_{	ext{eff}}$) is correct?

Accepted Answer

$Z_{	ext{eff}}$ increases across a period due to increased nuclear charge and poor shielding by valence electrons.

Question 15

Which of the following is a hydrate?

Accepted Answer

CuSO\_4 \cdot 5H\_2O

Question 16

How many molecules are present in 0.25 mol of glucose (C\_6H\_{12}O\_6)? (Avogadro's number = $6.022 	imes 10^{23}$)

Accepted Answer

$1.51 	imes 10^{23}$

Question 17

Which of the following elements is most likely to be diamagnetic in its ground state?

Accepted Answer

Ne

Question 18

Which of the following is the correct name for the compound Fe\_2O\_3?

Accepted Answer

Iron(III) oxide

Question 19

Which of the following is a correct formula for an ionic compound formed between magnesium and nitrate?

Accepted Answer

Mg(NO\_3)\_2

Question 20

Which of the following best describes the trend in metallic character across a period?

Accepted Answer

Metallic character decreases from left to right.

Study Guide: Periodic Properties and Molecules & Compounds (Chapters 3 & 4)

Study Guide - Practice Questions