$$5.00 \times \frac{100 \text{ cm}}{1 \text{ m}} \times \frac{1 \text{ in}}{2.54 \text{ cm}} = 197 \text{ in}$$

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

Question 1

Which statement best describes the Law of Definite Proportions as demonstrated by Joseph Proust?

Accepted Answer

Different samples of a pure compound always contain the same elements in the same mass ratio.

Question 2

Which experiment provided evidence for the existence of the atomic nucleus?

Accepted Answer

Rutherford Gold Foil Experiment

Question 3

A sample of CO$$_2$$ contains 12.0 g of carbon. According to the Law of Definite Proportions, how many grams of oxygen are present in the sample?

Accepted Answer

$$32.0 	ext{ g}$$

Question 4

Which of Dalton’s postulates was later found to be incorrect based on modern atomic theory?

Accepted Answer

Atoms are indivisible and indestructible.

Question 5

Using dimensional analysis, convert 5.00 meters to inches. ($$1 	ext{ m} = 100 	ext{ cm}$$, $$1 	ext{ in} = 2.54 	ext{ cm})$$

Accepted Answer

$$5.00 	imes \frac{100 	ext{ cm}}{1 	ext{ m}} 	imes \frac{1 	ext{ in}}{2.54 	ext{ cm}} = 197 	ext{ in}$$

Question 6

Which subatomic particle was discovered by J.J. Thomson using the cathode ray tube experiment?

Accepted Answer

Electron

Question 7

A neutral atom of silver ($$^{107}_{47}	ext{Ag}) $$has how many protons, neutrons, and electrons?

Accepted Answer

47 protons, 60 neutrons, 47 electrons

Question 8

Which of the following is a correct application of the Law of Multiple Proportions?

Accepted Answer

CO and CO$$_2$$ have ratios of carbon to oxygen that are simple whole numbers.

Question 9

Which element is a diatomic molecule at room temperature?

Accepted Answer

Oxygen ($$	ext{O}_2)$$

Question 10

A fluorine ion ($$	ext{F}^-) $$has 9 protons and 10 electrons. What is its net charge?

Accepted Answer

$$-1$$

Question 11

Which statement about isotopes is correct?

Accepted Answer

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

Question 12

Which group on the periodic table contains the noble gases?

Accepted Answer

Group 8A

Question 13

What is the mass number of $$^{207}_{82}	ext{Pb}^{3+}$$?

Accepted Answer

$$207$$

Question 14

Which of the following elements is a metalloid?

Accepted Answer

Silicon ($$	ext{Si})$$

Question 15

A cation is formed when an atom:

Accepted Answer

Loses one or more electrons

Question 16

Which of the following best describes the difference between a period and a group in the periodic table?

Accepted Answer

A period is a horizontal row; a group is a vertical column.

Question 17

Which experiment determined the charge of the electron?

Accepted Answer

Millikan Oil Drop Experiment

Question 18

If an atom has 17 protons, 20 neutrons, and 18 electrons, what is its net charge?

Accepted Answer

$$-1$$

Question 19

Which of the following is the correct formula for calculating the number of neutrons in an atom?

Accepted Answer

$$	ext{Number of neutrons} = A - Z$$

Question 20

Which of the following statements about the structure of the atom is correct according to Rutherford’s model?

Accepted Answer

Most of the atom's mass is concentrated in a small, dense nucleus.

General Chemistry: Atoms, Molecules, Ions, and Measurement Foundations

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