Topic 1 - (periodic table and elements and compounds) Flashcards
What are the 2 types of molecules?
Elements and compounds
What is an element?
More than 2 of the same atom or molecule
What is a compound?
More than 2 different elements chemically combined
Are compounds pure substances or mixtures?
Pure substances
What is a mixture?
2 or more different substances not chemically combined
Miscible
Can mix
Imiscible
Cannot mix
Why does distillation work?
because the substances have different boiling points, so the substances with the lowest boiling points will evaporate first
What is group 1 on the period table?
Alkali metals
What is group 7 on the periodic table?
Halogens
What is group 0/8 on the periodic table?
Noble gases
As you go down group 1 (alkali metals) …
- They get MORE reactive
- the atomic number increases
- the melting and boiling point DECREASES
As you go down group 7 (halogens)..
- they get LESS reactive
- the atomic number increases
- the melting and boiling point INCREASES
The Noble gases Group 0/8 …
- colourless
- unreactive
Why are the noble gases unreactive?
Because they have a full outer shell of 8 electrons
What are most of the elements on the periodic table?
METALS
What side are metals and non-metals on the periodic table?
Metals on the LEFT
Non-metals on the RIGHT
Some properties of metals are….
- conduct heat and electricity
- sonorous
- malleable
- ductile
Some properties of non-metals are….
- do NOT conduct heat or electricity
- are NOT malleable
- are NOT ductile
- are NOT sonorous
Do metals or non-metals have higher densities?
METALS
What is the difference between a compound and a mixture?
A compound has 2 or more different elements chemically combined
WHEREAS
A mixture has 2 or more different substances (elements or compounds) NOT chemically combined
What are some properties of group 1 alkali metals?
- can be easily cut with a knife
- low densities
- some float on water
What are the halogens?
Non - metals
What is a molecule?
2 or more atoms chemically combined
