Atomic Structure

Question 1

when and what did Dalton publish that revolutionised the world of chemistry? what did it state?

Answer 1

in 1803 he published his ideas about atom.

-all matter was made up of tiny solid balls called particles

Question 2

which 4 ideas did Dalton’s model include?

Answer 2

• atoms cannot be broken down into anything simpler
• the atoms of a given element are identical to each other
• the atoms of different elements are different from one another
• during chemical reactions atoms rearrange to make different substances

Question 3

why did Dalton’s model change over time?

Answer 3

due to the discovery of subatomic particles

Question 4

a timeline of discovery regarding subatomic particles: (5)

Answer 4

1897: Electrons

1909 - 1911: Atoms have a nucleus with electrons around it

1913: Electrons occupy shells (energy levels)
1918: Protons
1932: Neutrons

Question 5

3 main subatomic particles

Answer 5

• protons
• neutrons
• electrons

Question 6

why do atoms have a neutral charge?

Answer 6

-they have an equal number of protons and electrons

Question 7

structure of an atom:

Answer 7

• protons and neutrons in the nucleus

- electrons in the electron shells

Question 8

relative charge and mass of 3 main subatomic particles:

Answer 8

protons: +1, 1amu
neutrons: 0, 1amu
electrons: -1, 1/2000amu

Question 9

what is the AN? (atomic number)

Answer 9

of protons

Question 10

what is the AMN? (atomic mass number)

Answer 10

total # of protons and neutrons

Question 11

what are isotopes?

Answer 11

same # of protons but a different # of neutrons

Question 12

what is relative atomic mass?

Answer 12

weighted average of the relative atomic masses of the isotopes in an element.

Question 13

equation for relative atomic mass?

Answer 13

(abundance x mass) / 100 + (abundance x mass) / 100

Question 14

what is Ar?

Answer 14

relative atomic mass