Zusammenfassung der Ressource
WJEC Chemistry 2017 Unit 1
- Subatomic
particles
- How many neutrons are in a Neon atom?
- Neutrons = Mass number - Atomic number
- Protons= atomic number
Electrons= atomic number
- Protons = 10 Electrons = 10 Neutrons = ?
- N = 20 - 10
- Neutrons = 10
- Atomic
Structure
- Atoms have the electron structure of 2, 8, 8.
- What is the electron configuration of Neon?
- Protons = 10 Eletrons = 10 Neutrons = (20-10) 10
- 20 particles in
nucleus
- 10 electrons around outside
- = 2 , 8.
- What is the electron configuration of Iron?
- Electrons= 26
- Iron is in group 8
- The electronic structure of an atom in an element
is 2, 8, 8.
- So 26 has to fit into the outer shells. ( like shelves )
- =2, 8, 8, 8.
- The last number in the
configuration must match the
elements' group number.
- Isotopes
- Isotopes = elements with extra neutrons (more dense)
- Everything else about them is the same
- What is the Average Atomic Mass of Copper if...
- 69% is Cu63 and 31% is Cu65?
- (69 x 63) + (31 x 65) / 100
- average atomic mass = 63.62
- the atomic mass on a periodic table is usually rounded
to the nearest whole number or to one decimal place.
- (percentage1 x mass1) + (percentage2 x mass2) / 100
- Average atomic mass =
- Alkali Metals
(group 1 elements)
- Alkali Metals are stored in oil, as they
react with oxygen.
- Alkali metals react more as you move
down their group.
- Wants to loose outer electron to make a full
shell (bigger shells are easier to react)
- Halogens (group 7
elements)
- Halogens destroy cells (used in cleaning products)
- React less further down their group
(Need to gain 1 electron)
- The pull is weaker when a particle
has more shells
- Bond with metals to form metal Halides.
- Volatile =
Evaporate easily
- Flames and Precipitates
- Dip a wire loop into substances, then put loop
into flame. Watch coloured flame reaction.
- Green/Blue flame + Yellow precipitate
= Copper Iodide
- Orange flame + cream precipitate =
Sodium Bromide
- Silver nitrate + Halogen Ions =
Cream/white/yellow precipitate