$$1.661 \times 10$$^{-24}$$\ \mathrm{g}$$

Question 1

According to Richard Feynman, what is the single most important scientific statement that summarizes all scientific knowledge about matter?

Accepted Answer

Everything is made of atoms.

Question 2

Which of the following best describes a heterogeneous mixture?

Accepted Answer

A mixture in which the composition varies from one region to another.

Question 3

A bowl of noodle soup is used as an analogy for matter. Which part of the soup best represents a homogeneous mixture?

Accepted Answer

The broth, which is uniform throughout.

Question 4

Which of the following statements about atoms is TRUE?

Accepted Answer

Atoms are the smallest unit of matter that retains the properties of an element.

Question 5

Given the atomic number ($$Z) $$and mass number ($$A) of an $$atom, which formula correctly calculates the number of neutrons?

Accepted Answer

$$\mathrm{Number\ of\ neutrons} = A - Z$$

Question 6

Which subatomic particle has a mass approximately $$1/1836$$ that of a proton?

Accepted Answer

Electron

Question 7

If an atom has 11 protons, 12 neutrons, and 10 electrons, what is its net charge?

Accepted Answer

$$+1$$

Question 8

Which of the following is NOT a property that can be used to identify a substance?

Accepted Answer

Number of atoms in the universe

Question 9

Which statement about isotopes is correct?

Accepted Answer

Isotopes of an element have the same number of protons but different numbers of neutrons.

Question 10

Which scientist is credited with discovering the nucleus of the atom?

Accepted Answer

Ernest Rutherford

Question 11

A neutral atom of calcium ($$^{40}\mathrm{Ca}) $$has how many electrons?

Accepted Answer

20

Question 12

Which of the following best describes a compound?

Accepted Answer

A substance formed when two or more elements are chemically bonded in fixed proportions.

Question 13

What is the mass (in grams) of 1 atomic mass unit (amu)?

Accepted Answer

$$1.661 	imes 10$$^{-24}$$\ \mathrm{g}$$

Question 14

Which of the following particles has no electrical charge?

Accepted Answer

Neutron

Question 15

An atom of $$^{31}\mathrm{Ga} ($$Gallium) has how many neutrons?

Accepted Answer

20

Question 16

Which property is the same for all atoms of a given element?

Accepted Answer

Number of protons

Question 17

Which of the following is a physical property?

Accepted Answer

Color

Question 18

Which of the following is the correct symbol for the atomic number?

Accepted Answer

$$Z$$

Question 19

If an atom has a mass number of 23 and an atomic number of 11, what element is it and how many neutrons does it have?

Accepted Answer

Sodium, 12 neutrons

Question 20

Which of the following best explains why the atomic mass listed on the periodic table is not a whole number?

Accepted Answer

It is the average mass of all isotopes of that element, weighted by their natural abundance.

Matter, Atoms, and Subatomic Particles: Foundations of Chemistry

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