M3 - Periodicity, Groups 2 and 7 Flashcards
C
Are halogens oxidising or reducing agents?
Oxidising agents, as they themselves are reduced (electron acceptors)
A
Why are giant covalent lattices insoluble?
Covalent bonds holding it together are too strong to be broken by interaction with solvents.
What are the properties of giant covalent lattices?
High melting and boiling points
Insoluble in almost all solvents
Do not conduct (except for graphite and graphene)
formed from carbon, silicon anf boron
How were the elements ordered by Mendeleev?
Increasing atomic mass
B
what is produced when Ba is added to water?
Barium hydroxide and hydrogen gas
what is the colour of iodine in an organic solvent?
Purple
What is the name for the horizontal rows of the periodic table?
Periods
Define First Ionisation Energy (2)
The energy required to remove one electron from each atom (1) in one mole of gaseous atoms to form one mole of gaseous 1+ ions (1)
What causes the large jumps in successive ionisation energies?
Moving down to a closer shell, as these electrons are closer so experience a greater nuclear attraction.
What block is Lithium placed in and why?
Li is an S-block element - A s-block element has its highest energy/outermost electron in a s subshell/orbital
What is ionisation?
The removal of one or more electrons from an atom.
Which is the most reactive halogen and why?
Fluorine, as it has a small atomic radius and less shielding. Easier for fluorine to gain a electron
Why does ionisation energy increase across a period?
The number of protons in the nucleus increases so nuclear charge increases causing atomic radius to decrease, whilst shielding stays the same.
Complete the word equation;
HEAT
Calcium carbonate ->
Calcium oxide and carbon dioxide
How does electron shielding affect ionisation energy?
Inner shell electrons repel outer shell electrons, called shielding. This reduces the attraction between the nucleus and the outer electrons. therefore lower ionisation energy
In period 2, explain the fall of ionisation energy from nitrogen to oxygen
Nitrogen’s electrons in the 2p sub shell are unpaired so oxygen’s 8th electron is paired, causing repulsion and a lower ionisation energy.
what is the colour of aqueous chlorine?
Pale green
Why do most giant covalent lattices not conduct electricity?
All four outer shell electrons are involved in covalent bonding. No mobile charge carriers.
How does atomic radius affect ionisation energy?
Greater distance between the nucleus and outer electrons, the attraction is lower.
Explain the trend of first ionisation energy down a group
Atomic radius increases,
More shells so shielding increases,
Nuclear attraction on outer electrons decreases,
First ionisation energy decreases.
What is Successive Ionisation Energy?
A measure of the energy required to remove each electron in turn
In period 2, explain the fall from beryllium to boron of first ionisation energies
The new electron enters the 2p sub shell, which is slightly further away from the nucleus than the 2s sub shell.
What are common properties of metals?
Strong metallic bonds
High electrical conductivity
High melting and boiling points
What is meant by the term, Periodicity? (1)
The repeating trends in physical and chemical properties (1)
D
what is the colour of aqueous bromine?
Pale orange/brown
B
What is Disproportionation? (1)
The (simultaneous) oxidation and reduction of the same element (in the same redox reaction) (1)
How does nuclear charge affect ionisation energy?
More protons creates a greater attraction between the nucleus and the outer electrons. therefore higher ionisation energy
What is the name for the vertical columns of the periodic table?
Groups
what block are group 2 metals found in and why?
s block, as the highest energy/ outer electron is found within the s sub-shell / orbital
Who created the modern periodic table?
Dmitri Mendeleev
Define first ionisation energy
The energy required to remove one electron from each atom in one mole of gaseous atoms of an element to form one mole of gaseous 1+ ions.
what block are group 7 elements found in and why?
p block, as the highest energy/ outer electron is found within the p sub-shell / orbital
What predictions can be made from a graph of successive ionisation energies?
The number of electrons in the outer shell, the group of the element in the periodic table and thus the identity of the element.
How are elements arranged in the Periodic table? (2)
Elements are arranged by:
– Increasing atomic (proton) number (1) – In groups with similar chemical properties (1)
Define metallic bond
Strong electrostatic attraction between the cations and the delocalised electrons.
Define Second Ionisation Energy.
The energy required to remove one electron from each 1+ ion in one mole of
gaseous 1+ ions to form one mole of gaseous 2+ ions
Why do successive ionisation energies increase?
There are less electrons so the nuclear attraction on the remaining electrons will be greater.
Explain the general trend of first ionisation energy across a period
Nuclear charge increases, Same shell: similar shielding, Nuclear attraction increases, Atomic radius decreases, First ionisation energy increases.
C
In period 3, why does silicon have the highest melting point?
Forms a giant covalent lattice, where each atom is covalently bonded to four others. Strong covalent bonds.
Why do simple covalent molecules have low melting / boiling points?
Weak induced dipole-dipole forces between molecules are easy to break.
what is meant by thermal decomposition?
using heat energy to break bonds and break the substance down
what is the colour of aqueous iodine?
Pale brown
Why does the melting point and boiling point increase across the metals of a period?
Number of delocalised electrons per atom and charge on cation increase, so stronger electrostatic attraction. Stronger metallic bonds.
what is produced when CaO is added to water?
Calcium hydroxide
A
Why does ionisation energy decrease going down a group?
More electrons shells so the outer electrons are further away and there is a greater shielding effect.
What is metallic bonding?
Each atom donates an outer shell electron, which becomes delocalised. This creates cations.
Explain the trend of atomic radii across a period
Nuclear charge increases,
Nuclear attraction increases,
Atomic radius decreases across a period.
What is the periodic trend in electron configuration?
The sub shells of n energy level fill up.
Define second ionisation energy
The energy required to remove one electron from each ion in one mole of gaseous 1+ ions of an element to form one mole of gaseous 2+ ions.
