Periodicity Flashcards
What is periodicity?
Repeating trends of physical of chemical properties within increasing atomic number
What the bonding and structure Na, Mg and Al (period 3)?
Metallic bonding: strong electrostatic forces if attraction between positive ions and delocalised electrons
This forms a giant metallic lattice
What is the bonding of Si, P, S, Cl and Ar?
Covalent bond: shared pair of electrons between non metals
What is the bonding of Ar?
Monoatomic (single atom)
What crystal structure does Si form?
Macromolecular: Strong covalent bonds extend throughout
What crystal structure does P, S, Cl and Ar form?
Simple molecular : strong covalent bonds within the molecule and weak IMF
These are non polar so only have VDW forces
What is the boiling/melting point of Na, Mg and Al?
High MP & BP due to strong electrostatic attraction between positive ions and delocalised electrons
What is the boiling/melting point of Silicon
VERY HIGH due do strong covalent bonds which require alot of energy to break
What is the melting:boiling point of P, S, Cl and Ar?
Low mp & bp
have weak vdw forces between molecules that need to be broken
What happens to Atomic radius DOWN a group?
INCREASES
bc no. of shells increase
What happens to Atomic radius ACROSS a period?
DECREASES
-bc number of electrons in outer shell increase along with protons
-constant sheilding
-electors are more strongly attracted to nucleus and radius decreases
What is the trend in Ionisation energy in period 3?
increases as protons increase and shielding is constant
stronger attraction between nucleus and outer electron
Why is there a Deviation in ionisation energy in element Al?
-the ionisation energy is lower
-electron removed from higher energy p sublevel
-less energy required to remove electron
Why is there a Deviation in ionisation energy in element S?
There are 2 electrons in the same p orbital
they repel each other making it easier to remove the electron causing the ionisation energy to be lower than expected.
