Q: Which of the following is the correct formula for calculating the charge of an ion?

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

Question 1

Which statement best describes the main insight from Rutherford’s gold foil experiment?

Accepted Answer

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

Question 2

Which of the following is the correct formula for calculating the charge of an ion?

Accepted Answer

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

Question 3

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

Accepted Answer

11 protons and 11 electrons

Question 4

Which property is NOT characteristic of metals?

Accepted Answer

Tend to gain electrons in chemical reactions

Question 5

Which of the following best explains why the periodic table is organized by atomic number rather than atomic mass?

Accepted Answer

Atomic number reflects the number of protons, which defines the element.

Question 6

A chlorine atom has two naturally occurring isotopes: chlorine-35 (mass = 34.97 amu, abundance = 75.77%) and chlorine-37 (mass = 36.97 amu, abundance = 24.23%). What is the atomic mass of chlorine?

Accepted Answer

$$35.45\ 	ext{amu}$$

Question 7

Which of the following elements is a metalloid and is widely used in the electronics industry due to its semiconductor properties?

Accepted Answer

Silicon (Si)

Question 8

Which group in the periodic table contains elements that are chemically inert and do not readily form compounds?

Accepted Answer

Noble gases

Question 9

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

Accepted Answer

$$1-$$

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 experiment provided evidence that atoms have a small, dense nucleus?

Accepted Answer

Rutherford’s gold foil experiment

Question 12

What is the mass number of an isotope with 17 protons and 20 neutrons?

Accepted Answer

$$37$$

Question 13

Which of the following best describes the difference between cations and anions?

Accepted Answer

Cations are positively charged, anions are negatively charged.

Question 14

A sample of gallium 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

$$69.72\ 	ext{amu}$$

Question 15

Which of the following is a real-world application of radioactive isotopes in medicine?

Accepted Answer

Using technetium-99 to diagnose disease by imaging internal organs

Question 16

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

Accepted Answer

The periodic law summarizes observed recurring properties of elements.

Question 17

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

Accepted Answer

Magnesium (Mg)

Question 18

Which property is typical of nonmetals?

Accepted Answer

Tend to gain electrons in chemical reactions

Question 19

What is the main reason that black holes and neutron stars are so dense?

Accepted Answer

They are composed almost entirely of atomic nuclei packed closely together.

Question 20

Which of the following best describes the relationship between protons, neutrons, and electrons in a neutral atom?

Accepted Answer

The number of protons equals the number of electrons.

Atoms and Elements: Foundations of Matter and the Periodic Table

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