Question 1

An atom of bromine (Br) has an atomic number of 35 and a mass number of 80. How many neutrons are present in this atom?

Accepted Answer

45

Question 2

Which of the following elements is most likely to have chemical properties similar to krypton (Kr)?

Accepted Answer

Neon (Ne)

Question 3

Which group and period does selenium (Se, atomic number 34) belong to in the periodic table?

Accepted Answer

Group 6A, Period 4

Question 4

Which of the following lists contains only alkali metals?

Accepted Answer

Li, Na, K

Question 5

Which of the following is a property of metals?

Accepted Answer

High thermal and electrical conductivity

Question 6

How many valence electrons does an atom of aluminum (Al) have?

Accepted Answer

3

Question 7

According to the octet rule, how do elements on the right side of the periodic table typically achieve a stable electron configuration?

Accepted Answer

By gaining electrons to reach the next noble gas configuration

Question 8

Which of the following elements will form an ion with a charge of $$+3$$?

Accepted Answer

Aluminum (Al)

Question 9

A nonmetal atom gains two electrons. What is the resulting charge on the ion?

Accepted Answer

$$-2$$

Question 10

Which of the following best describes a metalloid?

Accepted Answer

Has properties intermediate between metals and nonmetals

Question 11

Which group contains the least reactive elements?

Accepted Answer

Group 8A (Noble Gases)

Question 12

What is the total number of electrons in a neutral atom of calcium (Ca, atomic number 20)?

Accepted Answer

20

Question 13

Which of the following elements is a nonmetal?

Accepted Answer

Oxygen (O)

Question 14

Which of the following is the correct electron configuration for an oxide ion ($$O^{2-}$$)?

Accepted Answer

$$1s^2$$ $$2s^2$$ $$2p^6$$

Question 15

Which of the following lists contains only metals?

Accepted Answer

Li, Na, K

Question 16

A patient is found to have a deficiency in potassium (K). Which group does potassium belong to, and what is a characteristic property of this group?

Accepted Answer

Group 1A; highly reactive and forms $$+1$$ ions

Question 17

Which of the following statements about the periodic law is correct?

Accepted Answer

The physical and chemical properties of elements are periodic functions of their atomic numbers

Question 18

If an atom has 17 protons, 18 neutrons, and 17 electrons, what is its atomic number and mass number?

Accepted Answer

Atomic number = 17, Mass number = 35

Question 19

Which of the following elements is a metalloid commonly used in semiconductors?

Accepted Answer

Silicon (Si)

Question 20

A neutral atom of barium (Ba) has an atomic number of 56. How many electrons does it have?

Accepted Answer

56

Atoms, Elements, and the Periodic Table: Study Guide for General Chemistry

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