Question 1

Which of the following statements best describes the difference between isotopes of the same element?

Accepted Answer

Isotopes have the same number of protons but different numbers of neutrons.

Question 2

A neutral atom of sulfur has an atomic number of 16 and a mass number of 32. How many protons, neutrons, and electrons does it contain?

Accepted Answer

16 protons, 16 neutrons, 16 electrons

Question 3

Which of the following elements is classified as a metalloid based on its position in the periodic table?

Accepted Answer

Silicon (Si)

Question 4

Which group of elements is characterized by being highly reactive, soft, shiny metals that react vigorously with water to form alkaline solutions?

Accepted Answer

Group 1A (Alkali metals)

Question 5

What is the electron configuration for magnesium ($$Z = 12$$)?

Accepted Answer

$$1s^2$$\ $$2s^2$$\ $$2p^6$$\ $$3s^2$$

Question 6

Gallium has two naturally occurring isotopes: $$^{69}\mathrm{Ga} ($$mass = 68.9257 amu, 60.4%) and $$^{71}\mathrm{Ga} ($$mass = 70.9248 amu, 39.6%). What is the atomic weight of gallium? (Round to two decimal places.)

Accepted Answer

$$69.72\ \mathrm{amu}$$

Question 7

Which of the following best describes the arrangement of electrons in the shells and subshells of an atom?

Accepted Answer

Electrons fill the lowest energy orbitals first, with each orbital holding up to two electrons of opposite spin.

Question 8

Which element has the following electron configuration: $$[\mathrm{Ne}]\ 3s^2$\ 3p^5$?

Accepted Answer

Chlorine (Cl)

Question 9

A certain atom has 28 protons, 28 electrons, and 32 neutrons. What is the symbol for this isotope?

Accepted Answer

$$^{60}_{28}\mathrm{Ni}$$

Question 10

Which of the following statements about noble gases is correct?

Accepted Answer

They are colorless, chemically unreactive gases found in group 8A.

Question 11

How many valence electrons does a tin (Sn) atom have, and what is its valence-shell electron configuration?

Accepted Answer

4 valence electrons; $$5s^2$$\ $$5p^2$$

Question 12

Which of the following is the correct electron-dot (Lewis) symbol for an element in group 5A?

Accepted Answer

The atomic symbol with five dots, with one pair and three single dots around it

Question 13

Which of the following best explains why alkali metals are never found in nature in their pure state?

Accepted Answer

They are highly reactive and readily combine with other elements.

Question 14

Which of the following elements is a main group element, based on its position in the periodic table?

Accepted Answer

Oxygen (O)

Question 15

If an atom has its first and second shells filled and four electrons in its third shell, what is the atomic number and the element?

Accepted Answer

Atomic number 14; Silicon (Si)

Question 16

Which of the following is the general valence-shell electron configuration for group 6A elements?

Accepted Answer

$$ns^2$$\ $$np^4$$

Question 17

Which of the following statements about the quantum mechanical model of the atom is correct?

Accepted Answer

Electrons are restricted to certain energy values, called quantized energy levels.

Question 18

Which of the following elements is most likely to be found as a diatomic molecule in nature due to its high reactivity?

Accepted Answer

Chlorine (Cl)

Question 19

Which of the following best describes the trend in atomic radius across a period in the periodic table?

Accepted Answer

Atomic radius decreases from left to right across a period.

Atoms and the Periodic Table: Structured Study Notes

Study Guide - Practice Questions

Study Guide - Flashcards