Question 1

Which of the following statements best describes an element?

Accepted Answer

An element is a pure substance that cannot be broken down into simpler substances.

Question 2

Which of the following elements is represented by the symbol $$\mathrm{K}$$?

Accepted Answer

Potassium

Question 3

A farmer applies magnesium sulfate to soil to improve plant growth. Which group does magnesium belong to on the periodic table?

Accepted Answer

Group 2A (2) - Alkaline earth metals

Question 4

Which of the following best describes the location and charge of a neutron in an atom?

Accepted Answer

Located in the nucleus, no charge

Question 5

Which experiment led to the discovery of the nucleus as a small, dense, positively charged center in the atom?

Accepted Answer

Rutherford’s gold foil experiment

Question 6

How many protons, neutrons, and electrons are present in an atom of $$^{35}_{17}\mathrm{Cl}$$?

Accepted Answer

17 protons, 18 neutrons, 17 electrons

Question 7

Which of the following is a property of metalloids?

Accepted Answer

They have properties intermediate between metals and nonmetals.

Question 8

Which element is a nonmetal in Group 5A (15)?

Accepted Answer

Nitrogen

Question 9

A sample of gallium contains 60.10% $$^{69}\mathrm{Ga} ($$atomic mass 68.926 amu) and 39.90% $$^{71}\mathrm{Ga} ($$atomic mass 70.925 amu). What is the atomic mass of gallium? (Round to two decimal places)

Accepted Answer

$$69.72\ \mathrm{amu}$$

Question 10

Which of the following electron configurations represents a neutral atom of oxygen?

Accepted Answer

$$1s^2$$\ $$2s^2$$\ $$2p^4$$

Question 11

Which of the following trends is correct for the atomic size of representative elements?

Accepted Answer

Atomic size increases from top to bottom within a group.

Question 12

Which of the following statements about ionization energy is true?

Accepted Answer

Ionization energy decreases down a group.

Question 13

Which element has the highest metallic character among the following: sodium, magnesium, aluminum, or phosphorus?

Accepted Answer

Sodium

Question 14

Which of the following best describes the Pauli exclusion principle?

Accepted Answer

Each orbital can hold a maximum of two electrons with opposite spins.

Question 15

Which of the following elements is essential for the formation of bones and teeth in the human body?

Accepted Answer

Calcium

Question 16

Which of the following is the correct Lewis symbol for nitrogen?

Accepted Answer

N with five dots around it

Question 17

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 18

Which of the following elements is a metalloid?

Accepted Answer

Silicon

Question 19

Which of the following best explains why the atomic mass of chlorine is not a whole number?

Accepted Answer

It is the average of the masses of all naturally occurring isotopes of chlorine.

Atoms and Elements: Structured Study Notes for GOB Chemistry

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