Atomic structure and Isotopes

Question 1

What are isotopes?

Answer 1

Atoms of the same element with the same number of protons but different number of neutrons.

Question 2

Relative atomic mass definition

Answer 2

-The weighted average mass of an atom of an element
-Taking into account its naturally occurring isotopes
-Relative to 1/12 the mass of carbon 12

Question 3

Relative molecular mass definition

Answer 3

-The mass of that molecule compared to 1/12 the atomic mass of an atom of carbon 12

Question 4

What is an orbital

Answer 4

A bit of space that an electron moves in

Question 5

SPDF NUMBER OF ORBITALS AND MAX ELECTRONS

Answer 5

-S=1 2
-P=3 6
-D=5 10
-F=7 14

Question 6

Ionic bonding is…

Answer 6

A result of an electrostatic force of attraction between oppositely charged ions.

Question 7

Why are ionic compounds solid at room temperature?

Answer 7

At room temperature there is not enough energy to overcome these strong electrostatic forces of attraction.

Question 8

What else does ionic attraction depend on?

Answer 8

-Ions that contain ions with greater ionic charges
-The size of the ions

Question 9

What two processes do solubility require in ionic compounds?

Answer 9

-The ionic lattice must be broken down
-Water molecules must attract and surround the ions

Question 10

(solubility) The higher the ionic charges in an ionic compound the..

Answer 10

Less soluble the substance is

Question 11

Why can’t solid ionic compounds conduct electricity?

Answer 11

-The ions are in a fixed position in the giant ionic lattice
-There are no mobile charge carriers.

Question 12

What is a covalent bond?

Answer 12

A shared pair of electrons

Question 13

How does bonding work in covalent molecules?

Answer 13

Atoms with covalent bonds are held together by electrostatic force of attraction between nuclei and shared electrons.

Question 14

What other things do covalent bonds depend on?

Answer 14

-How much the outer atomic orbitals of the bonded atoms overlap
-How strongly the atomic nuclei are attracted to the shared pair of electrons.

Question 15

How do you measure the strength of a covalent bond?

Answer 15

Average bond enthalpy

Question 16

What is co-ordinate/Dative covalent bonding?

Answer 16

-When one atom provides both the electrons.

Question 17

How do electrons repel each other?

Answer 17

Electrons are negatively charged so charged clouds repel each other until they are as far apart as possible.

Question 18

What is electronegativity

Answer 18

-The attraction of a bonded atom for the pair of electrons in a covalent bond.

Question 19

What is the trend of electronegativity?(WHY)

Answer 19

Going across the period electronegativity increases because…
-The nuclear charge increases
-Atomic radius decreases.

Question 20

What type of covalent bond is in a C-C molecule?

Answer 20

A pure covalent non polar bond
Because both atoms have the same electronegativity

Question 21

What type of covalent bond is found in a C-F bond?(WHY)

Answer 21

-It is a polar covalent bond
-Because there is a difference in electronegativity
-The greater the difference in electronegativity the more polar the covalent bond is

Question 22

How is a polar molecule formed?

Answer 22

When charge is distributed unevenly over a whole molecule and so will have a permanent dipole.

Question 23

A non-polar molecule is when…

Answer 23

polar molecules are arranged more symmetrically the dipoles cancel out

Question 24

A polar molecule is when..

Answer 24

Bonds are arranged so that they roughly point at the same direction so they don’t cancel out.

Question 25

What are covalent and intermolecular forces responsible for?

Answer 25

-Intermolecular=physical properties
-Covalent bonds=Chemical properties

Question 26

Induced dipole- dipole (London forces)

Answer 26

London dispersion forces arise due to temporary dipoles that are formed when electrons in a molecule are unevenly distributed.