Atomic Structure (unit1)

Question 1

What is the law of mass conservation and definite proportion?

Answer 1

mass conservation states that mass is neither created nor destroyed during a chemical reaction

definite proportions states that different samples of a pure substance always contain the same proportions of the same elements by mass.

Question 2

In what year was John Daltons atomic theory discovered?

Answer 2

1807

Question 3

What did John Dalton think about atoms and what did his theory suggest?

Answer 3

He thought atoms were as big as spheres and suggest that all atoms of the same element are exactly alike, atoms of different elements have different masses, atoms combine to form more complex structures and atoms cannot be broken down any further

Question 4

What changes were made to the atomic theory later on and describe the changes/

Answer 4

1897- Thomson
1909- Rutherford
1913- Bohr
1932- Chadwick
1932 and onwards- Schrödinger, Born, Heisenberg

Question 5

What are the relative mass and charges of protons , neutrons & electrons?

Answer 5

Protons- 1 & +1
Neutrons- 1 & 0
Electrons- 1/1836 & -1

Question 6

How can you find the direction of movement in a magnetic field?

Answer 6

Flemings left hand rule

Question 7

What does the nucleus contain and not contain?

Answer 7

Contains most mass of atoms which include protons and neutrons. Does not include electrons(which are outside the nucleus in the shell)

Question 8

What properties do beams deflect and not deflect?

Answer 8

Beams of proton and electron deflect in opposite direction of an electric magnetic field. Neutrons do not because it has no charge

Question 9

Definition of atomic mass, mass number & isotopes

Answer 9

is the number of protons in the nucleus of an atom (Z)

is the the number of protons plus neutrons in an atom (A). neutron- A-Z(mass number- atomic number)

are atoms with the same atomic number but different mass number

Question 10

What is relative atomic mass and isotopic mass? How to calculate Ar?

Answer 10

is the weighted average mass of atoms of an element on a scale where an atom of 12C has a mass of exactly 12 units (Ar)

is the mass of an isotope of an element on a scale where an atom of 12C has a mass of exactly 12 units

Calculate atomic mass= Ar- relative isotopic mass * relative abundance/100

Question 11

What are radioactive isotopes and emissions

Answer 11

are isotopes of some elements that have nuclei which break down spontaneously

are rays and particles given out as the nuclei breaks down

Question 12

Name 3 types of emission and uses of radioisotopes

Answer 12

alpha- helium nuclei, thin sheet of paper
beta- electrons, 6mm thick aluminium foil
gamma- very high frequency electromagnetic radiation, thick lead sheet

uses:
tracers for faults in pipelines eg 131 I
radiotherapy in treatment of cancers
dating the age of objects eg 14 C
smoke detectors use 241 Am

Question 13

What’s the difference in energy levels?

Answer 13

the energy difference between any two energy levels is given by energy=frequency of radiation

Question 14

How does an emission spectrum differ from a normal visible light spectrum?

Answer 14

its made up of separate lines
lines converge as their frequency increases

Question 15

What’s the Lyman series and Balmer series? Also the convergence limit

Answer 15

where previously excited electrons fall back to the n=1 energy level
where previously excited electrons fall back to the n=2 energy level

point where the lines eventually come together

Question 16

What’s an atomic orbital and electronic configuration?

Answer 16

is a region of space where there is a high probability of finding an electron. each orbital can hold a maximum of 2 electrons

shows the number and type of electrons in a particular atom

Question 17

What’s the first ionisation energy and what do the values depend on?

Answer 17

is the energy needed to remove a mole of electrons from a mole of gaseous atoms

values depends on nuclear charge, the distance of the outer electrons from the nucleus and shielding

Question 18

What are successive ionisation energies?

Answer 18

are the ionisation energy required to remove electrons one at a time from a mole of gaseous atoms