$$\text{Ion charge} = \text{number of protons} - \text{number of electrons}$$

Question 1

Which statement best describes the main contribution of John Dalton to atomic theory?

Accepted Answer

He formalized the atomic theory, stating that all matter is composed of tiny, indestructible particles called atoms.

Question 2

Which experiment led to the discovery that atoms have a small, dense nucleus?

Accepted Answer

Rutherford's gold foil experiment

Question 3

A neutral atom of magnesium has an atomic number of 12 and a mass number of 24. How many protons, neutrons, and electrons does it contain?

Accepted Answer

12 protons, 12 neutrons, 12 electrons

Question 4

Which of the following best explains why metals are good conductors of electricity?

Accepted Answer

They have loosely held electrons that can move freely.

Question 5

Which element is defined by having 17 protons in its nucleus?

Accepted Answer

Chlorine

Question 6

A fluorine atom gains one electron to form an ion. What is the charge of the resulting ion?

Accepted Answer

$$1-$$

Question 7

Which of the following is a property of nonmetals?

Accepted Answer

They tend to gain electrons in chemical reactions.

Question 8

Which of the following is the correct formula to calculate the charge of an ion?

Accepted Answer

$$	ext{Ion charge} = 	ext{number of protons} - 	ext{number of electrons}$$

Question 9

A sample of gallium contains 60.11% Ga-69 (mass 68.9256 amu) and 39.89% Ga-71 (mass 70.9247 amu). What is the atomic mass of gallium?

Accepted Answer

$$69.72$$ amu

Question 10

Which of the following statements about isotopes is correct?

Accepted Answer

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

Question 11

Which group in the periodic table contains elements that are all gases at room temperature and are chemically inert?

Accepted Answer

Noble gases (Group 8A)

Question 12

Which of the following best describes a cation?

Accepted Answer

An atom that has lost electrons and is positively charged.

Question 13

Which scientist is credited with arranging the periodic table by increasing atomic mass and recognizing recurring properties?

Accepted Answer

Dmitri Mendeleev

Question 14

A neutral atom of sodium (Na) has 11 protons. If it loses one electron, what is the symbol and charge of the resulting ion?

Accepted Answer

$$	ext{Na}^+$$

Question 15

Which of the following is a property of metalloids?

Accepted Answer

They have intermediate electrical conductivity that can be controlled.

Question 16

Which of the following best explains why the atomic mass listed in the periodic table is not a whole number?

Accepted Answer

It is the weighted average of the masses of all naturally occurring isotopes of that element.

Question 17

Which of the following elements is a halogen?

Accepted Answer

Chlorine

Question 18

A radioactive isotope is used in medical imaging. Which property makes it useful for this purpose?

Accepted Answer

It emits detectable radiation that can be traced inside the body.

Question 19

Which of the following statements about the distribution of mass in an atom is correct?

Accepted Answer

Most of the atom's mass is concentrated in the nucleus.

Question 20

If an isotope of carbon is represented as $$^{14}_{6}	ext{C}$$, how many neutrons does it have?

Accepted Answer

8

Atoms and Elements: Foundations of Matter (Chapter 4 Study Guide)

Study Guide - Practice Questions