Module 2 - Atoms and formulas

Question 1

what is an atom

Answer 1

basic building blocks

Question 2

what is the atomic structure

Answer 2

nucleus in a centre which consists of neutrons and protons. electrons within shells orbit nucleus

Question 3

relative mass and charge of proton

Answer 3

RM: 1
RC: +1

Question 4

relative mass and charge of neutron

Answer 4

RM: 1
RC: 0

Question 5

relative mass and charge of electron

Answer 5

RM: 1/2000
RC: -1

Question 6

what is an isotope?

Answer 6

atoms of the same element that has the same number of protons but different number neutrons.

Question 7

what letter presents the atomic number of an element

Answer 7

Z

Question 8

what letter represents the mass number of an element

Answer 8

A

Question 9

what does the group number of an element determine about an element

Answer 9

group number determines the outmost electrons

Question 10

how to calculate relative atomic mass

Answer 10

(abundance 1(%) x mass no1)+(abundance 2(%) x mass no2)

Question 11

dalton atomic theory

Answer 11

atoms can’t be divided
Small spheres

Question 12

J.J thompson discovery

Answer 12

Eeectrons are small by mass, negatively charged, can be deflected magnet

Question 13

plum pudding model

Answer 13

atoms are made up of negatively charged electrons around a sea of + charge

Question 14

rutherford experiment proved

Answer 14

mass is centred mostly in nucleus
electrons orbital the nucleus
volume of the atom is space between the nucleus and electrons

Question 16

what is the formula for:
nitrate
carbonate
sulfate
hydroxide
ammonium
zinc
silver

Answer 16

NO3 –
CO3 2-
SO4 2–
OH –
NH4 +
Zn 2+
Ag +

Question 16

what is a mole

Answer 16

amount of subastance
represents avagadros constant (6.02x10^23)

Question 17

current model of the atoms

Answer 17

protons and neutrons in nucleus
mass centred in nucleus
electrons orbit in shells
empty space between nucelus and electrons

Question 18

what is molar mass

Answer 18

mass per mole, units g mol–1
formula
mass/mole

Question 19

what is molar gas volume

Answer 19

gas volume per mole,
units dm3 mol–1

Question 20

how to calculate mole in a mass

Answer 20

mass=Mrmol

Question 21

how to calculate mole in a solution

Answer 21

concentration x volume

Question 22

how to calculate mole in a gas

Answer 22

given volume/ 24dm^3

Question 23

how to calculate number of particles

Answer 23

number of moles × (6.02×10^23)

Question 24

what is an empirical formula

Answer 24

simplest ratio of elements present in a compound.

Question 25

whats a molecular formula

Answer 25

number of each atom in a molecule.

Question 26

anhydrous compound definition

Answer 26

compound that doesn't contain water of crystallisation

Question 27

hydrated compound

Answer 27

ompound that does contain water of crystallisation

Question 28

water of crystallisation definition

Answer 28

compounds that can form crystals which have water

Question 29

number of moles

Answer 29

mass / molar mass

Question 30

# 1 mark Define the term atomic number.

Answer 30

Number of protons in the nucleus

Question 31

# 7 marks State the relative charge and relative mass of a proton, of a neutron and of an electron. In terms of particles, explain the relationship between two isotopes of the same element. Explain why these isotopes have identical chemical properties.

Answer 31

1.Proton: mass 1, charge + 1 2. Neutron: mass 1, charge 0 3. Electron mass 1/2000 4. Isotopes have the same number of protons 5. Different number of neutrons 6.Isotopes have same number of electrons 7. Chemical properties depend on electrons

Question 32

# 7 marks Define the term relative atomic mass. An element exists as a mixture of three isotopes. Explain, in detail, how the relative atomic mass of this element can be calculated from data obtained from the mass spectrum of the element.

Answer 32

1. Spectrum gives (relative) abundance 2. (formula) 3. And m/z 4. Multiply m/z by relative abundance for each isotope 5. Sum these values 6. Divide by the sum of the relative abundances

Question 33

# 3 marks Give two differences between the modern model of an atom and the Thomson model of an atom. Identity Difference 1 Difference 2

Answer 33

1. Boron 2. Protons in the centre of the atom/nucleus 3. Electrons are in shells/energy levels (around the nucleus)

Question 34

# 2 marks State two features of the current model that are not shown in the Rutherford model. Feature 1 of the current model Feature 2 of the current model

Answer 34

1. Current model includes: neutrons and protons 2. Current model shows electrons in different energy levels/orbitals