Question 1

Which of the following statements best describes the difference between a period and a group on the periodic table?

Accepted Answer

A period is a horizontal row, and a group is a vertical column.

Question 2

Which subatomic particle is responsible for the chemical properties of an element?

Accepted Answer

Electron

Question 3

An atom of magnesium has 12 protons and 13 neutrons. What is its mass number?

Accepted Answer

$25$

Question 4

Which of the following best explains why isotopes of the same element have different mass numbers?

Accepted Answer

They have different numbers of neutrons.

Question 5

Given the electron configuration $1s^2 2s^2 2p^6 3s^2 3p^1$, which element does this represent?

Accepted Answer

Silicon ($Si$)

Question 6

Which statement about the energy levels in an atom is correct?

Accepted Answer

Electrons in higher energy levels are farther from the nucleus.

Question 7

What is the maximum number of electrons that can occupy the $p$ sublevel in a given energy level?

Accepted Answer

$6$

Question 8

Which of the following elements has the highest metallic character?

Accepted Answer

Potassium ($K$)

Question 9

If an atom has an atomic number of $17$ and a mass number of $35$, how many neutrons does it have?

Accepted Answer

$18$

Question 10

Which of the following best describes the trend in ionization energy across a period from left to right?

Accepted Answer

Ionization energy increases.

Question 11

Which orbital diagram correctly represents the filling of electrons in the $2p$ sublevel?

Accepted Answer

Three boxes with one arrow in each box, all pointing up.

Question 12

Which of the following statements about valence electrons is correct?

Accepted Answer

Valence electrons determine the chemical reactivity of an element.

Question 13

Which element is located in Group 1A and Period 3 of the periodic table?

Accepted Answer

Sodium ($Na$)

Question 14

Which of the following is the correct electron configuration for a neutral atom of oxygen ($O$)?

Accepted Answer

$1s^2 2s^2 2p^4$

Question 15

Which of the following best explains why the atomic radius decreases across a period?

Accepted Answer

The nuclear charge increases, pulling electrons closer.

Question 16

Which of the following is true about the nucleus of an atom?

Accepted Answer

It contains protons and neutrons.

Question 17

Which of the following best describes the relationship between electromagnetic radiation frequency and energy?

Accepted Answer

Energy increases as frequency increases.

Question 18

Which of the following elements has the electron configuration $1s^2 2s^2 2p^6 3s^1$?

Accepted Answer

Sodium ($Na$)

Question 19

Which of the following is a correct statement about atomic number?

Accepted Answer

Atomic number is the number of protons in the nucleus.

Question 20

Which of the following best explains why elements in the same group have similar chemical properties?

Accepted Answer

They have the same number of valence electrons.

Atomic Structure, Periodic Table, and Periodic Trends: Study Notes for General Chemistry

Study Guide - Practice Questions