Atoms, Elements And Compounds

Question 1

What is an atom?

Answer 1

The smallest part of an element that can exist

Question 2

How are compounds formed?

Answer 2

By chemical reactions of elements

Question 3

Chemical reactions always involve…

Answer 3

The formation of one or more new substances

Question 4

What do compounds contain?

Answer 4

Two or more elements chemically combined in fixed proportions

Question 5

A mixture consists of…

Answer 5

Two or more elements or compounds not chemically combined together

Question 6

How can mixtures be seperated?

Answer 6

By physical processes (eg filtration, crystallisation, simple/ fractional distillation, and chromatography)

Question 7

What causes scientific models to be changed or replaced?

Answer 7

New experimental evidence

Question 8

What were atoms thought to be before the discovery of electrons?

Answer 8

Tiny spheres that could not be divided

Question 9

The discovery of the electron led to…

Answer 9

The plum pudding model

Question 10

What did the plum pudding show?

Answer 10

That an atom is a ball of positive charge with negative charge embedded in t

Question 11

The results from the alpha particle scattering experiment led to the conclusion that…

Answer 11

The nucleus was charged

Question 12

How did Niels Bohr adapt the nuclear model?

Answer 12

By suggesting that electrons orbit he nucleus at specific distances

Question 13

The relative charge kids proton is

Answer 13

+1

Question 14

The relative charge of a neutron is

Answer 14

0

Question 15

The relative charge of an electron is

Answer 15

-1

Question 16

The number of electrons is

Answer 16

Equal to the number of protons in the nucleus (atoms have no overall charge)

Question 17

Atomic number=?

Answer 17

The number of protons in an atom of an element

Question 18

Atoms have a radius of about

Answer 18

0.1 nm

Question 19

The radius of a nucleus is

Answer 19

Less than 1/10,000 of that of the atom

Question 20

The relative masses of

Answer 20

Proton: 1
Neutron: 1
Electron: very small

Question 21

The mass number is…

Answer 21

The sum of the protons and neutrons in an atom

Question 22

Isotopes are

Answer 22

Atoms of the same element that have a different number of neutrons

Question 23

What is the relative atomic mass?

Answer 23

He average value that takes amount of the abundance of the isotopes of that element

Question 24

The element in the periodic table are arranged in order of…

Answer 24

Atomic number so that elements with similar properties are in columns, aka groups

Question 25

Before the discovery of protons, neutrons and electrons, scientists ordered elements in order of their

Answer 25

Atomic weight

Question 26

How did the lack of knowledge on elements affect the arrangement of the early periodic table?

Answer 26

The table was incomplete and some elements were placed in inappropriate groups if the strict order of atomic weights was followed

Question 27

How did Mendeleev overcome problems with the early periodic table?

Answer 27

Left gaps for elements he thought had not been discovered and in some places changed the order based on atomic weights

Question 28

What are metals?

Answer 28

Elements that react to form positive ions

Question 29

What are non-metals?

Answer 29

Elements that do not form positive ions

Question 30

What are the group 0 elements known as and what are their properties?

Answer 30

The noble gases. Unreactive, and all have 8 electrons on their outer shell (except helium, which has 2 electrons)

Question 31

Why don’t noble gases easily form molecules?

Answer 31

Their atoms have stable arrangements of electrons

Question 32

The boiling points of the noble gases increase as…

Answer 32

You go down the group (increasing relative atomic mass)