Atomic structure and the periodic table

Question 1

Atomic number (Z)

Answer 1

The number of protons in the nucleus of an atom of that element

Question 2

Relative atomic mass

Answer 2

The average mass of an atom of an element on a scale where an atom of carbon-12 = 12

Question 3

Relative molecular mass

Answer 3

The average mass of a molecule on a scale where an atom of carbon-12 is 12

Question 4

Mass number (A)

Answer 4

The sum of the number of protons and neutrons in the nucleus of an atom of that isotope

Question 5

Relative isotopic mass

Answer 5

The mass of an atom of an isotope of an element on a scale when a carbon-12 atom is 12

Question 6

Isotopes

Answer 6

Atoms of the same element that have the same number of protons but different numbers of neutrons

Question 7

First ionisation energy

Answer 7

The energy required per mole to remove an electron from each atom in the gas phase to form single positive ion: M(g) -> M+(g) + e-

Question 8

Second ionisation energy

Answer 8

Energy required to remove one electron from each ion of a mole of gaseous singly charged positive ions of that element. M+ (g) -> M2+ (g) + e-

Question 9

First electron affinity

Answer 9

Energy change when one electron is added to each atom in a mole of neutral gaseous atoms: X(g) + e- -> X-(g)

Question 10

Second electron affinity

Answer 10

Energy change when one mole of gaseous 1- ions gain one electron per ion to produce 2- ions: X-(g) + e–> X2-(G=g)

Question 11

Electronegativity

Answer 11

The amount an atom attracts attracts the bonding pair of electrons in a covalent bond towards itself

Question 12

Effective nuclear charge

Answer 12

The net charge of the nucleus, after allowing for electrons in orbit around the nucleus shieling its full charge

Question 13

Mass spectrometer

Answer 13

A machine that determines the isotopic masses nd relative percentage abundances of the isotopes in an elemental sample