Elements of Life Flashcards
What are isotopes
Atoms of the same element with a different number of neutrons in the nucleus
Relative Atomic Mass = ?
(Relative isotopic mass x Relative abundance)/100
Speed of light in a vacuum
3x10^8 m/s
Wavespeed = ?
Wavelength x Frequency
Energy of a photon = ?
Planck constant x Frequency
Flame colours of lithium, sodium, potassium, calcium, barium, and copper
Li+ -- Bright red Na+ -- Yellow K+ -- Lilac Ca2+ -- Brick red Ba2+ -- Apple green Cu2+ -- Blue green
The four main points of Bohr’s theory
- Electrons only exist in certain definite energy levels or electron shells
- A photon of light is emitted when electrons change from one energy level to another
- The energy of the photon is equal to the different between the two energy levels
- E = hv
How many electrons can an orbital hold and how many orbitals per subshell
Each orbital can hold two electrons
- 1 orbital in s sub-shell
- 3 orbitals in p sub-shell
- 5 orbitals in d sub-shell
- 7 orbitals in f sub-shell
Which elements have a strange electronic structure?
Copper and chromium. The 4s orbital contains only one electron rather than two
Melting and boiling points across period 3
Both melting and boiling points initially increase but fall dramatically after silicon. This means the bonds in phosphorous must be weaker and easier to overcome than those between silicon
Covalent bonding
A bond in which electrons are shared between atoms
Four points needed to answer a shape and bond angle question
- The shape and the bond angle
- The number of areas of electron density
- Electrons repel to get as far away as possible
- Lone pairs repel more than bond pairs
2 x bond pairs
180 degrees, linear
3 x bond pairs
120 degrees, trigonal planar
4 x bond pairs
109.5 degrees, tetrahedral
2 x bond pairs, 1 x lone pair
107 degrees, bent
2 x bond pairs, 2 x lone pairs
104.5 degrees, bent