U1S1 atomic structure Flashcards
1
Q
What are the three sub atomic particles in atoms
A
- neutrons
- electrons
- protons
2
Q
What is the relative mass of protons and neutrons
A
1
3
Q
What is the relative mass of electrons
A
1/2000
4
Q
What does mass number show
A
- the total number of protons and neutrons in the nucleus of an atom
5
Q
What is the atomic number
A
- the number of protons in the nucleus of an atom
- defines the atom
6
Q
How are ions formed
A
- by losing or gaining electrons
7
Q
What is an isotope
A
- same number of protons
- different number of neutrons
8
Q
What decides the chemical properties of an element
A
- electron arrangement and number
9
Q
What determines an atoms physical properties
A
- its mass
10
Q
John dalton
A
- start of 19th century
- solid spheres
- different spheres make different elements
11
Q
Jj thompson
A
- 1897
- discovered electrons
- plum pudding model
12
Q
Rutherford
A
- 1909
- gold foil experiment where they fired alpha particles at a thin sheet of gold foil
- expected most to be deflected slightly
- most passed straight through, some deflected backwards
- tiny, positive nucleus surrounded by cloud of electrons
13
Q
Bohr
A
- electrons exist in fixed orbits
- each shell has a fixed energy level
- when an electron moves between shells, electromagnetic radiation is released or absorbed
14
Q
Relative atomic mass
A
- average mass of an atom of an element on a scale where an atom of carbon-12 is exactly 12
15
Q
Relative isotopic mass
A
- mass of an atom of an isotope of an element on a scale where carbon 12 is exactly 12
16
Q
Relative molecular mass
A
- average mass of a molecule on a scale where an atom of carbon 12 is exactly 12
17
Q
Relative formula mass
A
- average mass of a formula unit on a scale where an atom of carbon-12 is exactly 12
