Q: What is the charge and relative mass of an electron?

Charge $$= -1$$, mass $$= 9.11 \times 10$$^{-31}$$\ \mathrm{kg}$$

Question 1

Which statement best describes John Dalton's contribution to atomic theory?

Accepted Answer

He proposed that atoms are indivisible and cannot be created or destroyed in chemical reactions.

Question 2

According to the law of constant composition, which of the following is true for water ($$\mathrm{H_2O}$$)?

Accepted Answer

Water always contains $$11.2\%$$ hydrogen and $$88.8\%$$ oxygen by mass, regardless of the source.

Question 3

Which experiment led to the discovery of the electron?

Accepted Answer

Thomson's cathode ray tube experiment

Question 4

What did Rutherford's gold foil experiment reveal about atomic structure?

Accepted Answer

Atoms have a dense, positively charged nucleus where most of the mass is concentrated.

Question 5

Which particle was discovered by James Chadwick?

Accepted Answer

Neutron

Question 6

If an atom has 17 protons, 18 neutrons, and 17 electrons, what is its atomic number and mass number?

Accepted Answer

Atomic number $$= 17$$, mass number $$= 35$$

Question 7

Which of the following best explains why alpha ($$\alpha) $$particles were deflected in Rutherford's experiment?

Accepted Answer

They encountered a dense, positively charged nucleus.

Question 8

What is the charge and relative mass of an electron?

Accepted Answer

Charge $$= -1$$, mass $$= 9.11 	imes 10$$^{-31}$$\ \mathrm{kg}$$

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

A sample contains $$2.0$$ grams of hydrogen and $$16.0$$ grams of oxygen. How many grams of water ($$\mathrm{H_2O}) $$can be formed?

Accepted Answer

$$18.0$$ grams

Question 11

Which of the following is the SI unit for electric charge?

Accepted Answer

Coulomb ($$\mathrm{C})$$

Question 12

Which type of radiation is unaffected by an electric field?

Accepted Answer

Gamma ($$\gamma) $$radiation

Question 13

If a neutral atom of sodium ($$\mathrm{Na}) $$has an atomic number of $$11$$ and a mass number of $$23$$, how many neutrons does it contain?

Accepted Answer

$$12$$ neutrons

Question 14

Which law states that the total mass of reactants equals the total mass of products in a chemical reaction?

Accepted Answer

Law of conservation of mass

Question 15

Which of the following best describes the difference between protons and neutrons?

Accepted Answer

Protons have a positive charge, neutrons are neutral.

Question 16

A certain element has two naturally occurring isotopes: $$^{35}\mathrm{Cl} (75.8$$%) and $$^{37}\mathrm{Cl} (24.2$$%). What is the average atomic mass of chlorine?

Accepted Answer

$$35.48\ \mathrm{u}$$

Question 17

Which statement about the modern atomic model is correct?

Accepted Answer

Most of the atom's volume is occupied by electrons, while the nucleus contains most of the mass.

Question 18

Which scientist measured the charge of the electron using the oil drop experiment?

Accepted Answer

Robert Millikan

Question 19

Which of the following is a correct statement about ions?

Accepted Answer

Cations are positively charged ions formed by loss of electrons.

Question 20

A neutral atom of carbon has 6 protons and 6 neutrons. If it gains two electrons, what is its resulting charge?

Accepted Answer

$$-2$$

Atoms, Molecules, and Atomic Structure: Foundations of General Chemistry

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