Chemistry - End of Year 9 Exam

Mass Number

Protons + Neutrons

Atomic Number

Number of Protons

Charge

Protons - electrons

(If no charge, then electrons = protons)

Protons and protons do what

Repel

Electrons and electrons do what

Repel

Protons and electrons do what

Attract

Number of electrons in the first shell

2 electrons

Number of electrons in the second shell

8 electrons

Number of electrons in the third shell

18 electrons

To have full shells, atoms do what?

Atoms gain and lose electrons

Cations are…

Positive ions (more protons than electrons)

Anions are…

Negative ions (more electrons than protons)

Metal ion naming convention

Element name

Non-metals ion naming convention

Add ‘ide’

Isotopes are what?

Atoms with more or less neutrons

Exothermic

Releases heat

Endothermic

Absorbs heat

What is radiation?

When atoms become unstable and begin to fall apart

Alpha Radiation

When the nucleus is too large

Loses 2 protons and 2 neutrons

Element changes due to loss of protons, becomes new element + alpha particle

Beta radiation

When there are too many neutron

Gains proton, loses a neutron

Beta particle is an electron with high energy

Gamma radiation

Too much energy leads to emission of electromagnetic radiation

Element stays the same, just adds energy