Basic Atomic Theory Definitions

Question 1

Element

Answer 1

A substance that cant be divided any further by chemical means

Question 2

Compound

Answer 2

Two or more elements chemically combined

Question 3

Atom

Answer 3

The simplest part of an element which still retains the properties of that element

Question 4

Molecule

Answer 4

Two or more atoms chemically combined

Question 5

Mass number

Answer 5

Number of protons and neutrons in an element

Question 6

Atomic Number

Answer 6

Number of protons in an element

Question 7

Ion

Answer 7

A charged atom

Question 8

Isotopes

Answer 8

Atoms of the same element with the same atomic number but different mass numbers

Question 9

Anion

Answer 9

When an atom gains electrons it forms a negatively charged ion

Question 10

Cation

Answer 10

When an atom loses electrons it forms a positively charged ion

Question 11

Relative Atomic Mass

Answer 11

The average mass of the naturally occurring isotopes of an atom, taking into account their abundances, relative to 1/12th of the mass of an atom of carbon -12 which is defined as having a mass of 12

Question 12

Charge Mass and Position of Protons, Neutrons and Electrons

Answer 12

Protons : +1 1 In Nucleus
Neutrons : 0 1 In Nucleus
Electrons : -1 1/1840 Orbits Nucleus

Question 13

Why is the atomic number also equal to the number of electrons

Answer 13

Because atoms are neutral and protons are positive then the number of protons (positive charge) must be cancelled out by the same number of negative charges (electrons)

Question 14

How do you calculate the number of neutrons

Answer 14

Minus atomic number by mass number. Mass number always biggest number

Question 15

How do you calculate relative atomic mass

Answer 15

Multiply the mass of each isotope by its percentage occurrence and divide by 100