1
Q
element
A
a substance that can not be broken down into simpler substances through chemical methods
2
Q
atom
A
the smallest unit of an element, having properties of that element
3
Q
compound
A
a substance formed by 2 or more elements, combined chemically in a fixed ration
4
Q
molecule
A
a group of 2 more more atoms combined chemically
5
Q
Dalton’s Theory (4)
A
- all matter is made of atoms that are indivisible and indestructible
- all atoms of an element have identical masses and properties
- compounds are formed by a combination of two or more different types of atoms
- a chemical reaction is a rearrangement of atoms
6
Q
Thomson (Maltese cross) (6)
A
- filament (heated)
- Vacuum (in the glass tube)
- metal cross (filament projected light onto)
- fluorescent screen
- a filament was heated to create electrons, a light beam was shot at a cross that was negatively charged or positively charged. The reactions occurring differed by either having just the optical light (negative and negative) and a fluorescent light (negative and positive)
- plum pudding model
7
Q
Rutherford (nuclear model) (7)
A
- three type of radiation discovered (Alpha +2, Gamma 0, Beta -1)
- alpha particle source
- fluorescent screen
- metal foil
- deflected particles
- undeflected particles
- he used an Alpha particle source to shoot the particles at a metal foil (gold) to which he notice the rebound of some of the particles, this was surprise because the Alpha particles were higher in mass and positively charged (this meaning the discovery of the atom have a positively charged centre which was high mass and very small (nucleus)
8
Q
Bohr (“Bohr’s” model) (4)
A
- the discovery of having quantised orbitals around the nucleus
- proton (mass 1) (charge +1)
- Neutron (mass 1) (charge 0)
- electron (mass 1/2000) (charge -1)
9
Q
symbols (5)
A
- z (atomic number / proton number)
- X (Symbol of element)
- a (mass of number / nucleon number = no. Pro + no. Neu)
- larger of 2 is mass, smaller is atomic
- in a non isotope electrons are = to protons
10
Q
isotopes (3)
A
- atoms of the same element with different mass numbers
- calculate = (mass of one) x (percentage out of 100 atoms) + (mass of the other) x (percentage out of 100 atoms)
- abundance = sub in x and y, then solve using the simultaneous equation method
11
Q
mass spectrometer (5)
A
- ionisation ( the method of bombarding solid or gas phase electron with energetic electrons to for ions)
- acceleration ( the ions are accelerated to specific velocity)
- deflection ( the particles are then deflected by an electromagnetic field)
- detection (the beams of ions passing though are electrically detected)
- heavier means the less the deflection moves, lighter means the more they moved
12
Q
ions (3)
A
- the loss or gain of an electron/s
- positive (cation, lost an electron)
- negative (anion, gained an electron)
13
Q
electronic structure (6)
A
- can be used to identify unknown elements in a compound
- electron energy increases causing the outer electrons to move further away from the nucleus and then return releasing the gained energy in the form of light
- ground state (lowest energy state)
- excited state (electrons jumping to a higher energy level)
- ionisation energy (the energy required to remove the outer most electron from a gaseous atom in it’s ground state)
- second ionisation energy (same as the first except it the second most outer electron)
14
Q
trends (4 x 1/2)
A
- higher energy required across a Period
- greater nuclear attraction - lower energy required down a group
- further from the nucleus
15
Q
electron configuration (4)
A
- Heisenberg’s Uncertainty Theory - we never know where an electron is at a given moment, we can calculate the probability of the area it possibly is.
- no more than 2 electrons can occupy an orbital, and when they do they must spin in different directions
- electrons will occupy the orbital with the lowest possible energy
- an electron would rather occupy an orbital alone than share it
16
Q
Aufbau diagrams (2)
A
- s orbital (2)
- p orbital (6 = 2px, 2py, 2pz)
17
Q
Sp Notation (2)
A
- orbital
- to the power of electrons in that orbital
e. g) O = 1s2, 2s2, 2p4
s - chemistry
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