Q: Which of the following is the correct formula to calculate 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

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 of the following is a property of metals?

Accepted Answer

They are malleable and ductile.

Question 4

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

Accepted Answer

$$-1$$

Question 5

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

Accepted Answer

Carbon

Question 6

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? Use the formula: 
$$	ext{Atomic mass} = (	ext{fraction}_1 	imes 	ext{mass}_1) + (	ext{fraction}_2 	imes 	ext{mass}_2)$$

Accepted Answer

$$35.45$$ amu

Question 7

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

Accepted Answer

Noble gases

Question 8

What is the correct isotope symbol for an atom with 15 protons and 16 neutrons?

Accepted Answer

$$^{31}_{15}\mathrm{P}$$

Question 9

Which of the following best explains why metals are used in electrical wiring?

Accepted Answer

Metals are good conductors of electricity due to their ability to lose electrons easily.

Question 10

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

Accepted Answer

$$\mathrm{F}^-$$

Question 11

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

Accepted Answer

Dmitri Mendeleev

Question 12

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 13

Which of the following is a property of metalloids?

Accepted Answer

They have intermediate electrical conductivity that can be controlled.

Question 14

A magnesium atom loses two electrons during a chemical reaction. What is the symbol and charge of the resulting ion?

Accepted Answer

$$\mathrm{Mg}^{2+}$$

Question 15

Which of the following best describes the difference between the plum-pudding model and the nuclear model of the atom?

Accepted Answer

The nuclear model has a small, dense nucleus containing protons and neutrons, with electrons in a cloud around it.

Question 16

Which of the following elements is a halogen?

Accepted Answer

Chlorine

Question 17

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

Accepted Answer

It emits energetic subatomic particles that can be detected externally.

Question 18

How many neutrons are in an isotope of carbon with a mass number of 14?

Accepted Answer

8

Question 19

Which of the following best explains why lightning occurs during an electrical storm?

Accepted Answer

Negative charge builds up on clouds and positive charge on the ground, leading to a rapid rebalancing of charge.

Question 20

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

Accepted Answer

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

Atoms and Elements: Foundations of Chemistry

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