Chapter 3 Sec. 2 & 3 Inro to Atomic Structure

1. Which of the following is not one of the five principles contained in Dalton’s theory?

• All of matter is composed of extremely small particles called atoms

• In chemical reactions, atoms are created, destroyed, or changed

• Atoms of different elements differ in their physical and chemical properties

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

1. The table below gives information about the nucleus of each of four atoms.

How many different elements are represented by the nuclei in the table?

• 1

• 2

• 3

• 4

1. Which subatomic particle is negatively charged?

• Electron

• Neutron

• Positron

• Proton

1. What is the mass number of a carbon atom that contains six protons, eight neutrons, and six electrons?

• 6

• 8

• 14

• 20

1. What is the total number of electrons in an atom

of potassium?

• 18

• 19

• 20

• 39

1. A proton has a charge that is opposite the charge of

• An alpha particle

• An electron

• A neutron

• A positron

1. The diagram below represents the nucleus of an atom.

What are the atomic number and mass number of this atom?

• The atomic number is 9 and the mass number is 19

• The atomic number is 9 and the mass number is 20

• The atomic number is 11 and the mass number is 19

• The atomic number is 11 and the mass number is 20

1. What can be determined if only the atomic number of an atom is known?

• the total number of neutrons in the atom, only

• the total number of protons in the atom, only

• the total number of protons and the total number of neutrons

• the total number of protons and the total number of electrons

1. In his atomic model, Rutherford could not explain behavior of

• electrons

• protons

• neutrons

• neutrino

Rutherford's gold foil experiment showed that the atom is mostly empty space because

• some of the alpha particles were reflected right back

• some of the alpha particles were deflected

• most of the alpha particles went straight through the foil

• all of the alpha particles went straight through the foil