Relative Isotopic Mass?
Is the mass of an isotope, relative to 1/12 of the mass of an atom of carbon -12
Relative atomic mass?
Is the weighted mean mass of an atom of an element, relative to 1/12 of the mass of an atom of carbon 12
How is an ion formed?
By the loss or gaining of electrons
Relative charge of a proton?
+1
Relative charge of a neutron?
0
Relative charge of an electron?
-1
What is the mass number?
The biggest number, contains protons and neutrons
What is the proton number?
number of protons + electrons
Calculating relative atomic mass
- 78 % of chlorine -35
- 22% of chlorine -37
75.78 x 35 + 24.22 x 37 / 100
Calculating moles?
How many moles of phosphorus pentoxide (P4O10) are in 85.2g?
P= 31
O=16
31x4 +16x10 = 284
85.2 / 284 = 0.3 moles
Relative molecular mass?
N2 = 14 x 2 = 28
Relative atomic mass?
Copper: 120.8% = 63
54% = 65
120.8 x 63 + 54 x 65/ 174.8
= 63.6
Stages of mass spectrometry?
Gas injected in ionizer with electrons.
Beam of electrons is bombarded at electrons and sample is ionized.
Ions are accelerated in an electric field.
Then bend through magnetic field.
Deflected by electric field.
What is the vacuum for in a mass spectrometer?
Means there’s no interference from other ions.
High energy electrons are used to make the positive ion
Flame test: sodium chloride?
Yellow/ orange
Flame test: Lithium chloride?
red/ pink
Flame test: Calcium chloride?
yellow/ orange
Flame test: Barium chloride?
green
Flame test: Copper chloride?
Green/blue
Flame test: Potassium chloride?
lilac/ pink
Emission spectra?
If an electron takes in energy from its surroundings it’s excited to a higher energy level. When they drop to a lower energy level, they release this energy. (this is what we observe)
how many electrons does the S orbital hold?
2 electrons
How many electrons does the P orbital hold?
6 electrons
How many electrons does the D orbital hold?
10 electrons
How many electrons does the F orbital hold?
14 electrons
First 7 electronic configuration?
1s2s2p3s3p4s3d
Electronic configuration of Argon? 18 electrons
1s2, 2s2, 2p6, 3s2, 3p6
Using the noble gas in the above row to shorten electronic configuration
Scandium 21 Argon = 18
(Ar) 3s2, 3p1
Hunds rule?
Electrons will occupy the orbitals singularly before pairing takes place.
Pauli’s exclusion principle?
2 electrons cannot occupy the same orbital, unless they have opposite spins.
Chromuim and copper exceptions?
Both their 3d orbitals fill before their 4s orbitals
Which shell empties first when forming ions, 3d or 4s?
4s, because it takes less energy.
First ionisation energies?
Is the energy needed to remove 1 electron from each atom, in 1 mole of gaseous atoms to form 1 mole of gaseous 1+ ions
First Ionisation energies?
Generally INCREASE across a period
DECREASE down a group
First ionisation energies, exceptions?
groups 2+3 and 5+6
Atomic radius? (distance from the nucleus)
The more shells an atom has, and therefore the further away the outer electrons are from the nucleus, the less attraction they experience!
Nuclear charge?
The more protons, the greater the nuclear charge, the greater the attraction they experience!
Electron shielding
As the number of electrons between outer electrons and the nucleus increases, the outer electrons feel less attraction towards the nuclear charge (shielding)
First ionisation energy of chlorine?
Cl (g) — Cl+ (g) + e-
Second Ionisation energies?
Each ionisation energy is greater than the last!
Shells are drawn slightly closer to the nucleus when electrons are removed, because there is less repulsion.
Successive ionisation energies?
As you remove electrons, you’re pulling against the positive nucleus, therefore there is less repulsion between the electrons and each shell will be drawn slightly closer to the nucleus.
Successive ionisation energies on graphs?
The rise indicates the jump to the next quantum shell.
Periodicity?
studying of the trends as we go across the periodic table
Atomic radius DECREASES across a period.
because the increase in protons and electrons fills more shells, and therefore shielding increases
NUCLEAR CHARGE INCREASES across the periodic table
because the number of protons in the nucleus increases
Period 3
ATOMIC radius increases as you go down the table
