Periodic Table Trends Flashcards
(45 cards)
what is first ionisation energy
first ionisation energy as the removal of 1 mol of electrons from 1 mol of gaseous atoms
how is the periodic table arranged
- by increasing atomic (proton) number
- showing repeating trends in physical and chemical properties (periodicity)
- in groups having similar chemical properties
what is metallic bonding
metallic bonding as strong electrostatic attraction between cations (positive ions) and delocalised electrons
what structure do all metals have
giant metallic lattice structure
examples of solid giant covalent lattices of carbon
diamond graphite and graphene
outer shell electron configuration of group 2 elements
outer shell electron configuration is s2
what ions are formed in redox group 2 reactions
loss of these electrons in redox reactions to form 2+ ions
a use of Ca(OH)2
in agriculture to neutralise acid
uses of Mg(OH)2 and CaCO3
antacids’ in treating indigestion.
nth ionisation energy equation
X(n-1)+(g) –> e- + Xn+(g)
where is the s-block
group 1 2 and H
where is the p-block
group 3 4 5 6 7 8
where is the d-block
transition metals
how would you describe solid giant covalent lattices of carbon (diamond, graphite and graphene) and silicon
as networks of atoms bonded by strong covalent bonds
the outer shell electron configuration of group 2
the outer shell electron configuration is s2
what ion do group two form
loss of these electrons in redox reactions to form 2+ ions
relative reactivities of the Group 2 elements Mg → Ba shown by their redox reactions with oxygen, water and dilute acids
increases down group (reactions with water) Mg - VERY slowly Ca - steadily Sr - fairly quickly Ba- rapidly
group 2 metal plus water
makes metal hydroxide and hydrogen
M + 2H2O –> M(OH)2 + H2
group 2 metal plus oxygen
forms solid white oxides
2M + O2 –> 2MO
group 2 metal plus dilute acid
produces salt plus hydrogen
e.g. hydrochloric acid produces metal chloride and hydrogen
M + 2HCl –> MCl + H
trend in reactivity in terms of ionisation energy down group 2
as you go down the group, ionisation energies decrease. this is due to increasing atomic radius and shielding effect.
when group 2 element react they lose electrons, forming cations. the easier it is to lose electrons ( lower the ionisation energies), the more reactive the element so reactivity increases.
water and group 2 oxides
oxides of group 2 react readily with water to form metal hydroxides, which dissolve. the hydroxide ions OH-, make these solutions strongly alkaline.
(Mg is an exception - it only reacts slowly and the hydroxide isn’t very soluble)
the oxides form more alkaline solutions as you go down the group because the hydroxides get more soluble
e.g. CaO + H2O –> Ca2+ + 2OH-
how do halogens exist
halogens exist as diatomic molecules
explain the trend in the boiling points of Cl2, Br2 and I2, in terms of induced dipole–dipole interactions (London forces)
increase down the group because of the increasing strength of the London forces as the size and relative mass of atoms increases
