Structure 3 Flashcards
Periodicity
A repeating pattern in the chemical and physical properties of elements - when elements are arranged according to their atomic number
Across a period, atomic radius
Decrease
Down a group, atomic radius
Increase
Positive ions have (bigger/smaller) radius than the atom it’s derived from
Smaller
Isoelectronic positive ions (increase/decrease) in size across a period
Decrease
Isoelectronic
Same number of electrons
Negative ions have (smaller/larger) radius than the atom they are derived from
Larger
Isoelectronic negative ions (increase/decrease) across a period
Decrease in size across a period
What is ionisation energy?
The enthalpy change when an electron is removed from an atom in the gaseous state
Is removing an electron an exothermic or endothermic process?
Endothermic
Across a period, the electrons are more difficult to remove because ..
The increase in the nuclear charge increases the attraction between the nucleus and the valence electron
Down a group, the electrons are easier to remove because …
There is an increased distance between the valence electron and the nucleus
Electron affinity
The enthalpy change when an electron is added to an isolated atom in the gaseous state
Electron affinity equations must include
States
Electron affinity values generally increase …….. and ……..
Across a period and up a group
What is electronegativity?
A relative measure of the attraction that an atom has for a shared pair of electrons when it is covalently bonded to another atom
Does electronegativity apply to all groups?
No not group 18
Across a period, electronegativity (increases/decreases) due to ….
Increases, the increase in nuclear charge
Down a group, electronegativity (increases/decreases) due to ….
Decreases, the bonding electrons are furthest from the nucleus
Physical properties of alkali metals
- Good conductors of electricity and heat
- Low density, can float on water
- Shiny grey surfaces when freshly cut
Chemical properties of alkali metals
- Very reactive
- Form ionic compounds with non-metals
Physical properties of halogens
- Coloured
- Show a gradual change from gases, to liquids, to solids
What 2 halogens are gases?
F2 and Cl2
What halogen is a liquid?
Br2
What 2 halogens are solids?
I2 and At2
Chemical properties of halogens
- Very reactive non-metals
- Form ionic compounds with metals
- Form covalent compounds with other non-metals
When chlorine is bubbled through a bromide solution, what is the colour change?
Colourless to orange
When chlorine is bubbled through an iodine solution, what is the colour change?
Colourless to dark orange/brown
Are metal oxides lewis acids or lewis bases?
Lewis bases
What is a Lewis base? What does it react with?
They can donate an electron pair, and they react with water to form hydroxides
Amphoteric
It can act as an acid or a base
Are non-metal oxides Lewis acids or Lewis bases?
Lewis acids
What is a Lewis acid? What does it react with?
They can accept an electron pair, and they react with water for form other acids by accepting an electron pair from oxygen in water.
What is acid rain produced by?
Non-metal oxides
Where do sulfur oxides originate from?
Burning of fossil fuels
Where does nitrogen monoxide originate from?
Internal combustion engines
How does ocean acidification occur?
As carbon dioxide dissolves in the ocean
Free element oxidation state rule
Atoms in a free element have an oxidation state of zero
Simple ion oxidation state rule
The oxidation state is the same as the charge on the ion
Polyatomic ion oxidation state rule
The oxidation states of all the atoms in a polyatomic ion must add up to the ion’s charge.
Neutral compound oxidation state rule
The oxidation states of all the atoms in a neutral compound must add up to zero.
Element in a compound oxidation state rule
The usual oxidation state for an element in a compound is the same as the charge on its most common ion.
O oxidation state rule, and its two exceptions
O has the oxidation state of -2.
Except in peroxides, it is -1, and when bonded to fluorine, it is +2.
Cl oxidation state rule, and its exception
Cl has the oxidation state of -1. Except when it is bonded to the more electronegative F and O.
H oxidation state rule, and its exception
H has the oxidation state of +1.
Except when bonded to group 1 and 2 metals, when ionic hydrides are formed, when it is -1.
Binary ionic compounds are named by: and, what is the suffix
The cation, then the anion. The suffix is -ide.
SO4^2- IUPAC name and roman numeral
sulfate (VI)
SO3^-2 IUPAC name and roman numeral
sulfate (IV)
NO3^- IUPAC name and roman numeral
nitrate (V)
NO2^- IUPAC name and roman numeral
nitrate (III)
An increase in the oxidation state is called
Oxidation
A decrease in the oxidation state is called
Reduction
Disproportionation
Where the same element is oxidised and reduced simultaneously in the same reaction.
Three steps to naming organic compounds
- Longest carbon chain
- Functional groups, and their position
- Named alphabetically
How to name functional groups (as in, how to give them a number)
The number is the smallest possible when counting from the left or right.
For what three functional groups, is the functional group (in the naming of organic compounds) named first?
Alkyls, halogenalkanes, and ethers
For what functional group are two separate words used?
Esters
Skeletal formulas remove what two elements, where?
C and H bonds, at every point in the line at which the direction changes, including the start and the end
The lines in skeletal formulas must represent
Bond angles
What are the three types of structural isomers?
Chain, position, or functional group isomers
How do chain isomers differ from other structural isomers?
In the length of the longest carbon chain
How do position isomers differ from other structural isomers?
In the position of the functional group (s) in the molecule
How do functional group isomers differ from other structural isomers?
In the type of functional group in the molecule
Primary, secondary and tertiary apply to what functional groups?
Alcohols, halogenalkanes, and amines
Describe how to find a primary, secondary or tertiary molecule
The (OH, Cl, Br, I, F, NH3 (molecule)) is attached to one carbon atom which is attached to (one, two, three) other carbon atoms.
