Bonding

Question 1

An element

Answer 1

Substance that can’t be split up into simpler substances by chemical means

Question 2

Compound

Answer 2

Substance that’s made up of 2/ more elements combined chemically

Question 3

Atomic no.

Answer 3

No of protons in the nucleus of that atom

Question 4

Mass no.

Answer 4

Sum of protons+neutrons in the nucleus of an atom of that element

Question 5

Octet Rule

Answer 5

When bonding occurs, atoms want to reach 8 electrons in their outer shell

Question 6

Ion

Answer 6

A charged atom/ group of atoms

Question 7

Ionic bond

Answer 7

Force of attraction between oppositely charged ions in a compound. Always formed by the complete transfer of electrons from one atom to another

Question 8

Transition metal

Answer 8

Forms at least one ion with a partially filled d sublevel

Question 9

Molecule

Answer 9

Group of atoms joined together. The smallest particle of an element that can exist independently

Question 10

Valency of an element

Answer 10

The no. of atoms of hydrogen or any other monovalent element with which each atom of the element combines

Question 11

Sigma bond

Answer 11

Formed by the head-on overlap of two orbitals

Question 12

Pi bond

Answer 12

Formed by the sideways overlap of p orbitals

Question 13

Electronegativity

Answer 13

The relative attraction that an atom in a molecule has for the shared pair of electrons in a covalent bond

Question 14

Polar covalent bond

Answer 14

A bond in which there is unequal sharing of the pair of electrons. This causes one end of the bond to be slightly more positive (delta+) and the other to be slightly more negative (delta-)

Question 15

Intramolecular bonding

Answer 15

Bonding that takes place within a molecule, it holds the atoms together. E.g. Covalent and polar covalent bonding

Question 16

Intermolecular forces

Answer 16

Attractive forces between molecules. E.g Van der Waals forces, dipole-dipole forces and hydrogen bonding

Question 17

Van der Waals forces

Answer 17

Weak attractive forces between molecules resulting from the formation of temporary dipoles. The only forces of attraction between non-polar molecules

Question 18

How can a molecule with polar bonds be non-polar?

Answer 18

They are symmetrical molecules where the centre of the partial negative charge coincides with the partial positive charge

Question 19

Predict the shape of boron trifluoride

Answer 19

Trigonometry planar (3 pairs of electrons all in the same place and no lone pairs)

Question 20

What does an increase in electronegativity value indicate?

Answer 20

There’s an increasing no. of protons, atomic mass and nuclear charge
And a decrease in atomic radius

Question 21

How did Mendeleev predict the properties of unknown elements?

Answer 21

He used the properties of known elements to predict the properties of other elements f the same group. He arranged the elements in order of increasing atomic mass and left gaps in his table for undiscovered elements