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Flashcards in 1a. Periodicity Deck (14)
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1

What is covalent radius?

Half the distance between bonding nuclei

2

Why is there no covalent radii for the Noble Gases?

They do not form covalent bonds.

3

What is the trend for covalent radius across a period?

Decreases due to greater pull of extra protons on shells

4

What is the trend for covalent radius down a group?

Increases due to greater number of electron shells (levels)

5

Why is there no covalent radius for the Noble Gases?

There are no bonding nuclei to measure between.

6

What is 1st Ionisation energy?

The energy required to remove 1 mole of electrons from 1 mole of atoms in the gaseous state

7

What is the trend for ionisation energy across a period?

Increases due to greater pull of extra protons on outer electrons

8

What is the trend for ionisation energy going down a group?

Decreases due to greater shielding effect of extra shells and greater distance of outer electrons from nucleus

9

Why is 2nd ionisation energy always greater than the 1st?

It takes more energy to remove an electron from a positively charged ion 

10

Why is the 2nd ionisation energy of group 1 metals so much higher than the 1st?

or

Why is the 3rd ionisation energy of group 2 metals so much higher than the 2nd?

or

Why is the 4rd ionisation energy of group 3 metals so much higher than the 3rd?

  • electron is being removed from a stable (full) shell or electron arrangement
  • this shell has less shielding effect from the nucleus
  • this shell lies closer to the nucleus

11

What is electronegativity?

The attraction an atom's nucleus has for bonding electrons

12

What is the trend fo electronegativity down a group

Decreases due to

  •  greater shielding effect of extra shells
  •  greater distance of bonding electrons from nucleus

13

What is the trend for electronegativity across a period

Increases due to

  • greater pull of extra protons on shared pair of electrons
  •  bonding electrons lying closer to nucleus

14

Why is there no electronegativity value for the noble gases?

They do not form (covalent) bonds due to having a complete outer shell