GCSE - Topic 2 - Seperation - Year 9 Flashcards
What charge do atoms have?
Atoms are neutral - they have no overall charge. This is because they have the same number of protons and electrons.
How are compounds formed?
When elements react, atoms combine with other atoms to form compounds.
What are compounds?
Substances formed from two or more elements
What is group 1 called?
The alkali metals.
What are the alkali metals like?
They’re soft and have low density.
What are the trends for the alkali metals as you go down the group?
- Increasing reactivity - the outer electron is more easily lost as the attraction between the nucleus and electron decreases because the electron is further away from the nucleus
- Lower melting and boiling point
- Higher relative atomic mass
What is the reaction between the alkali metals and water like?
- They react vigorously to produce hydrogen gas and metal hydroxides
- The more reactive the alkali metal is, the more violent the reaction
- The amount of energy given out by the reaction increases down the group.
What is group 7 called?
The halogens.
What do the halogens exist as?
Molecules, which are pairs of atoms.
What are the trends for the halogens as you go down the group?
- Become less reactive.
- High melting and boiling point.
- Higher relative atomic mass.
What is group 0 called?
The noble gases.
What are monatomic gases?
Single atoms not bonded together.
What colour are the group 0 elements at room temperature?
They’re colourless.
Are the group 0 gases inert?
Yes, this means they’re unreactive.
How does the boiling point change as you go down group 0?
The boiling point increases.
What is an ionic bond?
The electrostatic attraction between oppositely charged ions. (Involves a non-metal and metal)
What’s a covalent bond?
When non-metal atoms bond together, they share pairs of electrons to make covalent bonds.
What makes covalent bonds very strong?
The positively charged nuclei of the bonded atoms are attracted to the shared pair of electrons by electrostatic forces.
What’s a compound?
Two or more elements are chemically bonded together.
What is an ion?
An atom or group of atoms with a charge (from losing or gaining electrons).
How do you draw a covalent bond?
- Start with ‘share zones’
2. Put the rest of the electrons on the outside
What is filtration used for?
To remove insoluble solids.
What are the 4 state symbols?
(s), (g), (l), (aq)
What is distillation used for?
To separate 2 liquids based on their boiling points or to separate a soluble substance from a liquid.
