C1-Atoms, Molecules, Stoichiometry

Question 1

Nucleon number / mass number

Answer 1

Total no. of protons & neutrons in a nucleus of an atom of an element.

Question 2

Relative atomic mass, Ar

r is subscript

Answer 2

Average mass of isotopes of an element

relative to 1/12 of mass of 1 carbon-12 atom.

Question 3

Relative molecular mass, Mr

r is a subscript

Answer 3

Average mass of molecules

relative to 1/12 of mass of 1 carbon-12 atom

Question 4

Relative formula mass, Mr

r is a subscript

Answer 4

Average mass of formula units

relative to 1/12 of mass of 1 carbon-12 atom.

Question 5

Mole

Answer 5

Amount of substance

containing as many particles as no. of atoms in 12g of carbon-12.

Question 6

Relative isotopic mass

Answer 6

Mass of an isotope of an element relative to 1/12 of mass of 1 carbon-12 atom.

Question 7

Molar mass

Answer 7

Mass of 1 mole of subtance

Question 8

Empirical formula

Answer 8

Chemical formula which

shows simplest whole no. ratio of atoms

of each element in a compound.

Question 9

Molecular formula

Answer 9

Chemical formula which

shows actual no. of atoms

in a molecule or a formula unit.

Question 10

Orbital

Answer 10

Region of space around a nucleus

where there is a high probability of finding an electron

of a given energy level.