$$\text{Number of neutrons} = \text{mass number} - \text{atomic number}$$

$$^{12}_{6}\text{C}$$ and $$^{14}_{6}\text{C}$$

Question 1

Which of the following statements about elements is TRUE?

Accepted Answer

Elements are pure substances that consist of only one type of atom.

Question 2

Which chemical symbol is derived from a Latin name?

Accepted Answer

Na for sodium

Question 3

What does the atomic number of an element represent?

Accepted Answer

The number of protons in the nucleus of the atom

Question 4

Which of the following elements is classified as a metalloid?

Accepted Answer

Silicon (Si)

Question 5

A neutral atom of aluminum has 13 protons. How many electrons does it have?

Accepted Answer

13

Question 6

Which statement best describes the difference between metals and nonmetals?

Accepted Answer

Metals are malleable and ductile, while nonmetals are brittle.

Question 7

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

Accepted Answer

Rutherford's gold foil experiment

Question 8

If an atom has an atomic number of 17 and a mass number of 35, how many neutrons does it have?

Accepted Answer

18

Question 9

Which of the following is the correct formula to calculate the number of neutrons in an atom?

Accepted Answer

$$	ext{Number of neutrons} = 	ext{mass number} - 	ext{atomic number}$$

Question 10

Which of the following pairs are isotopes of the same element?

Accepted Answer

$$^{12}_{6}	ext{C}$$ and $$^{14}_{6}	ext{C}$$

Question 11

Which subatomic particle has a negative charge?

Accepted Answer

Electron

Question 12

A sample contains two atoms: $$^{18}_{8}	ext{O}$$ and $$^{16}_{8}	ext{O}. $$What do these atoms have in common?

Accepted Answer

Same number of protons

Question 13

Which of the following is NOT a characteristic of metalloids?

Accepted Answer

They are good conductors of heat and electricity.

Question 14

Which group on the periodic table contains the noble gases?

Accepted Answer

Group 18

Question 15

An atom of lead (Pb) has a mass number of 207 and an atomic number of 82. How many neutrons does it have?

Accepted Answer

125

Question 16

Which of the following best describes Dalton's atomic theory?

Accepted Answer

Atoms of different elements combine in simple whole-number ratios to form compounds.

Question 17

Which of the following elements is essential to human health and is found in the periodic table's highlighted region for health?

Accepted Answer

Sodium (Na)

Question 18

A neutral atom has 20 protons and 22 neutrons. What is its atomic number and mass number?

Accepted Answer

Atomic number: 20, Mass number: 42

Question 19

Which of the following statements about isotopes is correct?

Accepted Answer

Isotopes of an element have the same atomic number but different mass numbers.

Question 20

Which of the following best explains why the mass of an atom is concentrated in its nucleus?

Accepted Answer

Protons and neutrons are located in the nucleus and have much greater mass than electrons.

Elements, Atomic Structure, and the Periodic Table: Week 2 Study Notes

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