Question

reviewing vocabulary
match each definition in column a with the term in column b.
column a

1. radiation deflected toward the positively charged plate
2. atoms with the same number of protons but different

numbers of neutrons

1. high - energy radiation that has no charge and no mass
2. the smallest particle of an element that retains the

properties of that element

1. the weighted average mass of an elements isotopes
2. the center - most part of an atom where the protons and

neutrons are contained

1. radiation deflected toward the negatively charged plate
2. the rays and particles emitted by radioactive material
3. equal to 1/12 the mass of a carbon - 12 atom
4. ray of radiation traveling from the cathode to the anode
5. process (not requiring energy) by which unstable nuclei

lose energy

1. states that all matter is composed of atoms
2. process whereby some substances spontaneously emit

radiation
subatomic particles and the nuclear atom
in your textbook, read about discovering the electron and the nuclear atom.
for each item in column a, write the letter of the matching item in column b.
column a

1. proposed the nuclear atomic model
2. determined the mass - to - charge ratio

of an electron

1. calculated the mass of an electron

Explanation:

• Column A 1: Beta radiation ($\beta$-radiation) is negatively charged. Opposite charges attract, so it is deflected toward the positively charged plate.
• Column A 2: Isotopes are atoms of the same element (same number of protons) but with different numbers of neutrons.
• Column A 3: Gamma rays ($\gamma$-rays) are high - energy radiation with no charge and (negligible) mass.
• Column A 4: An atom is the smallest particle of an element that retains the properties of that element.
• Column A 5: Atomic mass is the weighted average mass of an element’s isotopes.
• Column A 6: The nucleus is the center - most part of an atom containing protons and neutrons.
• Column A 7: Alpha radiation ($\alpha$-radiation) is positively charged. Opposite charges attract, so it is deflected toward the negatively charged plate.
• Column A 8: Radiation consists of the rays and particles emitted by radioactive material.
• Column A 9: An atomic mass unit (amu) is equal to \(1/12\) the mass of a carbon - 12 atom.
• Column A 10: Cathode rays are rays of radiation traveling from the cathode to the anode.
• Column A 11: Radioactive decay is the process (not requiring energy input) by which unstable nuclei lose energy.
• Column A 12: Dalton’s atomic theory states that all matter is composed of atoms.
• Column A 13: Radioactivity is the process whereby some substances spontaneously emit radiation.

• Subatomic Particles and the Nuclear Atom Column A 1: Rutherford proposed the nuclear atomic model.
• Subatomic Particles and the Nuclear Atom Column A 2: Thomson determined the mass - to - charge ratio of an electron.
• Subatomic Particles and the Nuclear Atom Column A 3: Millikan calculated the mass of an electron (using the charge from his oil - drop experiment and the mass - to - charge ratio from Thomson’s work).

Answer:

1. g
2. d
3. e
4. a
5. c
6. b
7. f
8. i
9. h
10. k
11. m
12. j
13. l

Subatomic Particles and the Nuclear Atom:

1. c
2. a
3. b