Year 9 term 1 science yearly

Period

Period

The horizontal rows in the periodic table. Atoms in the same period have the same number of shells

Group

The vertical columns in the periodic table. Atoms in the same group have the same number of valence electrons.

Valance electrons:

The electrons located at the outermost shell of an atom

How to find number of protons in an atom

Atomic number

How to find number of electrons in an atom

Atomic number

How to find number of neutrons in an atom

Atomic weight - number of protons

Ions

An atom that has a positive or negative charge as a result of gaining or losing electrons.

Cations

Positive ions. Formed with atoms in the groups 1,2,3,4. (e.g sodium)

Anions

Negative ions. Formed with atoms in the groups 5,6,7,8. (e.g fluorine)

What will react easily

Elements that can give each other full shells (e.g sodium and fluorine)

Metal properties

Good conductors of heat and electricity, Shiny, ductile, malleable, reaction with water = corrosion, Mostly solids

Non metals

Poor conductors of heat and electricity, Dull, not ductile, Brittle, Mix of solids, liquids and gases 

Metalloids

Mix of metals and non metals

Alkali metals properties

soft and silvery, very reactive (especially with water) and always bonded with other elements in nature

Alkaline earth metals

white and malleable, reactive (but not as much as alkali metals), very good conductors of electricity and always bonded with other elements in nature

transition metals

 Good conductors of heat and electricity, Able to put 32 electrons in their second last shell, Have 1 or 2 valence electron, Combine chemically with oxygen

boron family

majority are metals except boron which is a metaloid. Stable and fairly unreactive

carbon family

Metals, metaloids and non metals. Stable and fairly unreactive

Nitrogen family

Metals, metaloids and non metals. Can share electrons to form compounds

Oxegen family

Contains metals, metaloids, non metals. Highly reactive

Halogens

non-metals and very reactive. They mostly react with alkali metals to form salts

nobel gasses

Non-reactive gasses that are found in earth’s atmosphere.

rare earth metals

Some are radioactive. Silver, silvery white and grey.

Isotopes

Different versions of an element as they have different amounts of neutrons. They are named after their mass number.

Radioisotopes

Isotopes that are unstable. The ratio of protons to neutrons is unbalanced and the nuclease will decay by emitting the three types of radiation, alpha, beta and gamma

Alpha radiation

This type of radiation is when an atom emits a helium nuclease. It is positive, with an atomic mass of 4 AMU. Its radiation penetration is low (shielding of paper) but has the highest ionising ability. When an atom releases this type of radiation, the atomic mass goes down by 4 and the atomic number decreases by 2. As the atomic number goes down by 2, the is now different. 

Beta radiation

This type of radiation is when an atom emits an electron. It is negative with an atomic mass of 1/2000 AMU. Its radiation penetration is intermediate (shielding of aluminium) with a medium ionising ability. When an atom releases this type of radiation, the atomic mass or number does not change.

Gamma radiation

This type of radiation is when an atom emits a high energy wave. It is neutral, with an atomic mass of 0 AMU. Its radiation penetration is very high (shielding of 2 inches of lead) but has a low ionising ability. When an atom releases this type of radiation, the atomic number and mass do not change. It often occurs with the other 2 kinds of radiation. 

Penetration

How much each radiation is able to get through different materials 

Ionising ability

Ability to add or lose/add electrons/protons by different amounts

Shielding

What material stops the radiation from getting through

Half life

Time taken for half the radioactive atom to decay