Elements, atomic structure, compounds and mixtures

Question 1

Is atomic number on the bottom or top?

Answer 1

Bottom

Question 2

Is mass number on the bottom or top?

Answer 2

Top

Question 3

How has the dalton model changed over time?

Answer 3

Due to discovery of subatomic particles

Question 4

Structure of an atom?

Answer 4

Contains a nucleus that is tiny in comparison to the overall atom and contains protons and neutrons surrounded by electrons in shells

Question 5

Protons
Relative charge;
Relative mass;

Answer 5

+1
1

Question 6

Neutrons
Relative charge;
Relative mass;

Answer 6

0
1

Question 7

Electrons
Relative charge;
Relative mass;

Answer 7

-1
0

Question 8

Why do atoms contain equal numbers of protons and electrons?

Answer 8

Because then their charges ‘cancel out’ so that the electrical charge overall is neutral

Question 9

Mass number is number of…?

Answer 9

Protons + neutrons

Question 10

Atomic number is the number of…?

Answer 10

Protons (or electrons)

Question 11

What are isotopes?

Answer 11

Atoms of the same element with the same number of protons but different numbers of neutrons

Question 12

Why can isotopes cause the relative atomic mass to not be a whole number?

Answer 12

Because when we calculate the atomic mass of an element as a weighted average of isotopic masses in relation to their natural abundance the number tends to be a decimal

Question 13

The periodic table is an arrangement of elements in order of….?

Answer 13

Atomic number

Question 14

What are groups in the periodic table?

Answer 14

Columns - elements in the same groups have the same number of electrons in their outer shells

Question 15

What are periods?

Answer 15

Rows - Same number of electron shells

Question 16

What are groups?

Answer 16

Columns - Same number of electrons in their outer shells

Question 17

What is relative atomic mass?

Answer 17

The average mass of an atom compared to 1/12 of the mass ^12C

Question 18

What factors increase the R of R?

Answer 18

Increase temperature
increase concentration
increase surface area
add a catalyst

Question 19

What did John Dalton’s theory state?

Answer 19

Atoms are tiny invisible particles
atoms of one element are all the same
atoms of different elements are different
compounds are formed by combining atoms

Question 20

what did J.J. Thomson discover?

Answer 20

That atoms are made from even smaller things, he discovered electrons with cathode rays. He likened atoms to plum puddings

Question 21

What did Ernest Rutherford disover?

Answer 21

The atom was 99% space, there must be a very dense centre - he called this the nucleus - which contained positive particles. Electrons must be outside the nucleus.

Question 22

What did James Chadwick discover?

Answer 22

a neutral particle - neutron

Question 23

What did Niels Bohr discover?

Answer 23

Electrons surrounded the nucleus in shells

Question 24

In Rutherfords experiment why did most alpha particles pass straight through the gold atom?

Answer 24

because most of an atom (99%) is just open space

Question 25

Why do some of the alpha particles deflect or bounce back in Rutherfords experiment?

Answer 25

there must be a very dense positive nucleus

Question 26

what can you use to measure the volume of gas more accurately?

Answer 26

use a gas syringe