Chapter 1 Definitions

Question 1

Atom

Answer 1

The smallest unit of matter, consisting of a nucleus (protons and neutrons) surrounded by electrons.

Question 2

Electron

Answer 2

A negatively charged subatomic particle found in the electron cloud around the nucleus of an atom.

Question 3

Proton

Answer 3

A positively charged subatomic particle found in the nucleus of an atom.

Question 4

Neutron

Answer 4

A neutral subatomic particle found in the nucleus of an atom, with a mass roughly equal to that of a proton.

Question 5

Electron Transition

Answer 5

The movement of an electron between different energy levels or orbitals within an atom

Question 6

Emission Spectrum

Answer 6

A spectrum of emitted light when electrons in an atom return to lower energy states, emitting photons of specific wavelengths.

Question 7

Continuous Spectrum

Answer 7

A spectrum that shows a continuous range of wavelengths of light, without gaps or lines.

Question 8

Energy Level

Answer 8

A specific region around the nucleus where electrons are likely to be found, corresponding to different energy states.

Question 9

Valence Shell

Answer 9

The outermost electron shell of an atom, involved in chemical bonding.

Question 10

Valence Electron

Answer 10

An electron in the outermost shell of an atom, which participates in chemical reactions.

Question 11

Atomic Number:

Answer 11

The number of protons in the nucleus of an atom, determining the element’s identity.

Question 12

Mass Number

Answer 12

The sum of protons and neutrons in the nucleus of an atom.

Question 13

Stable Octet

Answer 13

A stable arrangement of eight electrons in the valence shell of an atom, typically associated with noble gases.

Question 14

Ion

Answer 14

An atom or molecule that has gained or lost one or more electrons, resulting in a charged particle.

Question 15

Cation

Answer 15

A positively charged ion, formed when an atom loses electrons.

Question 16

Anion

Answer 16

A negatively charged ion, formed when an atom gains electrons.

Question 17

Multivalent

Answer 17

Describes an element that can form ions with different charges, such as transition metals.

Question 18

Polyatomic Ion

Answer 18

An ion made up of two or more atoms that are covalently bonded and carry a charge.

Question 19

Isotope

Answer 19

Atoms of the same element with the same number of protons but different numbers of neutrons.

Question 20

Isotopic Abundance

Answer 20

The relative percentage of each isotope of an element in a sample.

Question 21

Radioactive Decay

Answer 21

The process by which an unstable atomic nucleus loses energy by emitting radiation.

Question 22

Nuclear Radiation

Answer 22

Particles or electromagnetic radiation emitted from the nucleus of a radioactive atom.

Question 23

Alpha Particle

Answer 23

A particle consisting of 2 protons and 2 neutrons, emitted during radioactive decay.

Question 24

Beta Particle

Answer 24

A high-energy electron or positron emitted during radioactive decay.

Question 25

Gamma Ray

Answer 25

High-energy electromagnetic radiation emitted from the nucleus of a radioactive atom.

Question 26

Radioisotope

Answer 26

An isotope of an element that is unstable and undergoes radioactive decay.

Question 27

Average Atomic Mass:

Answer 27

The weighted average mass of an element's isotopes, based on their relative abundance.

Question 28

Group

Answer 28

A vertical column in the periodic table, containing elements with similar chemical properties.

Question 29

Period:

Answer 29

A horizontal row in the periodic table, indicating elements with the same number of electron shells.

Question 30

Periodic Law

Answer 30

The law stating that the chemical properties of elements are periodic functions of their atomic numbers.

Question 31

Lewis Symbol

Answer 31

A representation of an element's valence electrons as dots around the element's symbol.

Question 32

Atomic Radius

Answer 32

The distance from the nucleus of an atom to the outermost electron shell.

Question 33

Effective Nuclear Charge

Answer 33

The net positive charge experienced by an electron, considering both the full nuclear charge and electron shielding.

Question 34

Ionization Energy

Answer 34

The energy required to remove an electron from an atom or ion in the gas phase.

Question 35

Electron Affinity

Answer 35

The energy change that occurs when an electron is added to a neutral atom to form an anion.

Question 36

Successive Ionization Energy

Answer 36

The energy required to remove an electron from a positively charged ion, after one or more electrons have already been removed.

Question 37

Isoelectronic

Answer 37

Describes two atoms, ions, or molecules that have the same electron configuration.