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A Level Chemistry Year 1 > Atoms and Moles > Flashcards

Flashcards in Atoms and Moles Deck (56)
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1

What is the mass of an electron?

1/1840

2

What is an isotope?

An atom with the same number of protons but different number of neutrons

3

What is the atomic number?

Number of protons

4

Why do some atoms of the same element have different mass numbers?

If they have different number of neutrons

5

What do ions have different numbers of?

Protons and Electrons

6

What is the relationship between protons and electrons in a negative ion?

There are more electrons than protons

7

What is the relationship between protons and electrons in a positive ion?

There are more protons than electrons

8

What 2 things affects the chemical properties of an element?

Number and arrangement of electrons

9

Why do isotopes not change the chemical properties of an element?

Isotopes have the same configuration of electrons so they've got the same chemical properties

10

What 2 physical properties are different with isotopes compared to elements?

Different densities
Rates of diffusion

11

Who came up with one of the currently accepted models of the atom?

Bohr

12

What did some ancient Greeks believe matter was made of?

They believed matter was made from invisible particles

13

What did John Dalton describe atoms as at the start of the 19th century?

Solid spheres (different types of sphere made up of the different elements)

14

What did JJ Thomson conclude after his experiments in 1897?

That atoms weren't solid and invisible

15

What did Thomson call the 'electrons'?

Corpuscles

16

What was Thomson's model called?

Plum Pudding Model

17

What was the Plum Pudding model?

A positively charged sphere with negatively charged electrons embedded in it

18

What experiment did Rutherford conduct?

The gold foil experiment

19

What did Rutherford's gold foil experiment involve?

Firing alpha particles (+ve charge) at an extremely thin sheet of gold

20

What did Rutherford expect the result of his experiment to be (due to the Plum Pudding Model)?

That most of the alpha particles were to deflect slightly

21

What did Rutherford's gold foil experiment show?

That the plum pudding model was incorrect

22

What was the name of the model that Rutherford came up with?

Nuclear Model

23

What was the Nuclear Model?

An atom with a tiny, positively charged nucleus at the centre of it with a cloud of negative electrons

24

Where was most of the mass concentrated in the Nuclear Model?

At the centre, so most of the atom is empty space

25

What did Henry Moseley discover?

Charge of the nucleus increased from one element to another in units of one

26

After Moseley's discovery, what did Rutherford find when further investigating the nucleus?

That it called positively charged particles that he called protons

27

Who discovered the neutron?

James Chadwick

28

What were the 4 principals of Bohr's model?

-Electrons only exist in fixed orbits (shells) and not anywhere in between
-Each shell has a fixed energy
-When an electron moves between shells EM radiation is emitted or absorbed
-Because the energy of the shells is fixed, the radiation will have a fixed frequency

29

What did the Bohr model explain about noble gases?

Why they were inert (chemically inactive)

30

How did the Bohr Model explain why the noble gases are inert?

He said that atoms can only hold a fixed number of electrons in a shell, and that an element's reactivity is due to it's electrons. So, when a shell is full of electrons, it's stable and doesn't react