The energy required when one mole of gaseous atoms forms one mole of gaseous ions with a single positive charge
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2
Show first ionisation energy with hydrogen
H(g) --> H+ + e-
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3
Define second ionisation energy
The energy required when one mole of gaseous ions with a single positive charge forms one mole of gaseous ions with a double positive charge
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4
State the 4 factors affecting ionistion energy
Atomic radius
Nuclear charge
Shielding
Electron pair repulsion
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5
What happens to ionisation energy across a period?
INCREASES- The nuclear charge increases, causing a greater pull on the electrons and therefore more energy is required to remove electrons. There is a decrease between group2 and 3 as the p shells start to fill
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6
What happens to ionisation energy down a group?
DECREASES- due to the shielding of the outer electrons from the nucleus and so the attraction is weaker and they are more easily removed.
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7
Explain atomic emission spectra
Ground state--> absorb heat and become "excited"--> they then become less excited --> they emit energy in fixed amounts (light)
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8
How does ionisation energy show electron configuration?
From right to left you can see the levels which reflect the shells. This shows with group and period an element is in
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9
State the 4 subshells and how many electrons they contain
s- 2 p-6 d-10 f-14
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10
Define orbital
A region within an atom that can hold up to two electrons with opposite spins
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11
What is the shape of the s and p subshells?
s- spherical p- dumbbell
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12
How do electrons fill subshells?
They fill singly then into pairs with opposite spins ("bus theory")
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13
What are the 2 conditions in subshell filling
4s fills and empties before 3d
Cu and Cr are 4s1
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14
Which elements are in which block?
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15
Define periodicity
The repeating pattern of physical or chemical properties going across the periods
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16
Explain the trends in melting and boiling points in terms of bonding
Metallic bonding- strong bonds-->high melting and boiling points Ionic bonding- strong bonds-->high melting and boiling points Simple covalent- weak bonds--> low melting and boiling points Macromolecular- strong bonds--> high melting and boiling point
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17
Define ionic bonding
Electrostatic attraction between two oppositely charged ions
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18
Define covalent bonding
Electrostatic attraction between two nuclei and a shared pair of elctrons
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19
Describe the trend of ionic radii down the groups
The radii increases and there are more shells
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20
What is a dative covalent bond?
When the shared pair of electrons in the covalent bond come from only one of the bonding atoms
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