Atomic Structure

A neutral aluminium atom has

atomic number of 13,

mass number of 27,

therefore the atom has:

• 13 protons

  13 neutrons

  13 electrons

• 13 protons

  14 neutrons

  13 electrons

• 13 protons

  13 neutrons

  14 electrons

• 14 protons

  13 neutrons

  13 electrons

A magnesium atom has 12 protons, 12 neutrons and 10 electrons.

Therefore

• it is a positive ion

  as it has gained electrons

• it is a positive ion

  as it has lost electrons

• it is a negative ion

  as it has gained electrons

• it is a negative ion

  as it has lost electrons

An atom, or group of atoms,

that have lost or gained electrons

is called:

• molecule

• compound

• element

• ion

A substance that consists of only one atom type

is called:

• molecule

• compound

• element

• ion

A substance that consists of two or more different atom types

joined together by chemical bonds is called:

• molecule

• element

• compound

• ion

The atomic number of an atom is

• the number of protons

  in the nucleus

• the number of neutrons

  in the nucleus

• the number of protons

  plus

  the number of neutrons

  in the nucleus

• the number of protons

  plus

  the number of neutrons

  plus

  the number of electrons

The mass number is:

• the number of protons

  in the nucleus

• the number of neutrons

  in the nucleus

• the number of protons

  plus

  the number of neutrons

  in the nucleus

• the number of protons

  plus

  the number of neutrons

  plus

  the number of electrons

Assuming that all sub atomic particles are shown

and assuming protons are red, neutrons are yellow

and assuming electrons are blue,

the diagram represents

• a neutral oxygen atom

• a 2+ positive oxygen ion

• a 2- negative oxygen ion

• a neutral hydrogen atom

Calculation used to find the number of neutrons in an atom

• Mass Number

  minus

  Atomic Number

• Atomic Number

  plus

  Mass Number

• Mass Number

• Atomic Number

Calculation used to find the number of protons in an atom

• Mass Number

  minus

  Atomic Number

• Atomic Number

  plus

  Mass Number

• Mass Number

• Atomic Number