Nuclear Chemistry

Question 1

Transformations of atomic nuclei are fittingly called _____ reactions. Some spontaneous reactions occur at room temperature emits ___ and are said to be _____

Answer 1

nuclear reactions; radiation; radioactive

Question 2

Define nucleons

Answer 2

protons and neutrons

Question 3

All atoms of a given element have the same number of ____; this number is the element’s _____.

Answer 3

protons; atomic number

Question 4

Atoms of a given element can have different numbers of _____, which means they can have different _____.

Answer 4

neutrons; mass numbers

Question 5

Define mass number

Answer 5

total number of nucleons (protons + neutrons) in the nucleus

Question 6

Atoms with the same atomic number but different mass numbers are known as ____

Answer 6

isotopes

Question 7

Three naturally occurring isotopes of uranium. Rank in increasing natural abundances

Answer 7

uranium-238 (99.3%)
uranium-235 (0.7%)
uranium-234 (trace amount)

Question 8

Different isotopes of an element have different ____ and different _____

Answer 8

natural abundances and stabilities

Question 9

a nucleus containing a specified number of protons and neutrons

Answer 9

nuclide

Question 10

Nuclides that are radioactive are called ____, and atoms containing these nuclei are called ____

Answer 10

radionuclides; radioisotopes

Question 11

____ are unstable and spontaneously emit particles and electromagnetic radiation

Answer 11

Radionuclides

Question 12

How did unstable nucleus transform into a more stable one?

Answer 12

Emission of radiation that carries the excess energy

Question 13

The ___ are known as alpha (α) particles. Radioactive decay that involves this particle is called ___

Answer 13

helium-4 particles; alpha decay or alpha emission

Question 14

Radioactive decay was discovered by ____ in ____. He saw that photographic plates developed ____ when _____

Answer 14

Antoine Henri Becquerel in 1896

bright spots when exposed to uranium metals

Question 15

high-speed electrons emitted by an unstable nucleus

Answer 15

beta β particles

Question 16

In beta particles, the superscript 0 indicates that ______. The subscript -1 represents the _____ of the beta particle, which is opposite that of the proton.

Answer 16

the mass of the electron is exceedingly small relative to the mass of a nucleon

negative charge

Question 17

beta emission is equivalent to the conversion of a ___ to a ____

Answer 17

neutron to a proton

Question 18

consists of high-energy photons (electromagnetic radiation of very short wavelength) that changes neither the atomic number nor the mass number of a nucleus

Answer 18

gamma radiation

Question 19

a particle that has the same mass as an electron but opposite charge

Answer 19

positron

Question 20

has the effect of converting a proton to a neutron, thereby decreasing the atomic number of the nucleus by 1 while not changing the mass number

Answer 20

positron emission

Question 21

capture by the nucleus of an electron from the electron cloud surrounding the nucleus (electron is consumed)

Answer 21

electron capture

Question 22

Rank in increasing penetrating power
neutron, gamma ray, alpha ray, beta ray

Answer 22

alpha ray, beta ray, gamma ray, neutron