$$\text{Ion charge} = 17 - 18 = 1-$$

$$\text{Atomic mass} = (0.7577 \times 34.97) + (0.2423 \times 36.97) = 35.45\ \text{amu}$$

$$\text{Atomic mass} = (0.6011 \times 68.9256) + (0.3989 \times 70.9247) = 69.72\ \text{amu}$$

Question 1

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

Accepted Answer

He formalized the atomic theory, stating that elements are composed of tiny, indestructible particles called atoms.

Question 2

A neutral atom of sodium (Na) has an atomic number of 11. How many protons and electrons does it contain?

Accepted Answer

11 protons and 11 electrons

Question 3

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

Accepted Answer

Rutherford’s gold foil experiment

Question 4

Which of the following is a property of metals?

Accepted Answer

They are malleable and ductile.

Question 5

What is the charge on an ion with 17 protons and 18 electrons?

Accepted Answer

$$	ext{Ion charge} = 17 - 18 = 1-$$

Question 6

Which element is defined by having 6 protons in its nucleus?

Accepted Answer

Carbon

Question 7

A sample of chlorine contains 75.77% chlorine-35 (mass 34.97 amu) and 24.23% chlorine-37 (mass 36.97 amu). What is the atomic mass of chlorine?

Accepted Answer

$$	ext{Atomic mass} = (0.7577 	imes 34.97) + (0.2423 	imes 36.97) = 35.45\ 	ext{amu}$$

Question 8

Which of the following best describes a metalloid?

Accepted Answer

A substance with intermediate electrical conductivity, useful in electronics

Question 9

Which group in the periodic table contains the noble gases?

Accepted Answer

Group 8A

Question 10

How many neutrons are in an isotope of magnesium-25 ($$^{25}_{12}	ext{Mg}$$)?

Accepted Answer

$$25 - 12 = 13$$ neutrons

Question 11

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 12

Which of the following elements is most likely to form a $$2+$$ ion?

Accepted Answer

Magnesium (Mg)

Question 13

Which property is NOT typical of nonmetals?

Accepted Answer

Often shiny and malleable

Question 14

A technetium-99 ($$^{99}_{43}	ext{Tc}) $$isotope is used in medical imaging. How many protons and neutrons does it have?

Accepted Answer

43 protons and 56 neutrons

Question 15

Which of the following best explains why matter is usually electrically neutral?

Accepted Answer

Atoms contain equal numbers of protons and electrons.

Question 16

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

Accepted Answer

Dmitri Mendeleev

Question 17

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

Accepted Answer

$$	ext{Atomic mass} = (0.6011 	imes 68.9256) + (0.3989 	imes 70.9247) = 69.72\ 	ext{amu}$$

Question 18

Which of the following is a real-world application of a radioactive isotope?

Accepted Answer

Using technetium-99 to diagnose disease in patients

Question 19

Which of the following statements about the nuclear model of the atom is correct?

Accepted Answer

Most of the atom’s mass and all positive charge are in a small nucleus.

Atoms and Elements: Foundations of Matter and the Periodic Table

Study Guide - Practice Questions