2.1 Atomic Structure and Isotopes, 2.1.2 Compounds, Formula and Equations

Question 1

What was states in Dalton’s atomic theory? (4)

Answer 1

•Atoms are tiny particles made of elements
•Atoms cannot be divided
•All the atoms in an element are the same
•Atoms of one element are different to those of other elements

Question 2

What did Thompson discover about electrons?

Answer 2

•They have a negative charge
•They can be deflected with a magnet and electric field
•They have very small mass

Question 3

Explain the plum pudding model

Answer 3

Atoms are made up of electrons moving around in a sea of positive charge

Question 4

What was Rutherford’s proposal after the gold leaf experiment? (4)

Answer 4

•Most of the mass and positive charge of the atom are in the nucleus
•Electrons orbit the nucleus
•Most of the atom’s volume is the space between the nucleus and the electrons
•Overall positive and negative charges must balance

Question 5

Explain the current model of the atom

Answer 5

•Protons and neutrons are found in the nucleus
•Electrons orbit in shells
•Nucleus is tiny compared to the total volume of atom
•Most of the atom’s mass is in the nucleus
•Most of the atom is empty space between the nucleus and the electrons

Question 6

What is the charge of a proton?

Answer 6

1+

Question 7

What is the charge of an electron?

Answer 7

1-

Question 8

Which particle has the same mass as the proton?

Answer 8

Neutron

Question 9

Which two particles make up most of the atom’s mass?

Answer 9

Protons and neutrons

Question 10

Which letter is used to represent the atomic number of an atom?

Answer 10

Z

Question 11

What does the atomic number tell about an element?

Answer 11

Number of protons in an atom

Question 12

Which letter represents the mss number?

Answer 12

A

Question 13

How is mass number calculated?

Answer 13

Number of protons + number of neutrons

Question 14

How to calculate the number of neutrons?

Answer 14

Mass number - atomic number

Question 15

Define isotope

Answer 15

Atoms of the same element with different numbers of neutrons

Question 16

Why do different isotopes of the same element react in the same way? (2)

Answer 16

•Neutrons have no impact on the chemical reactivity
•Reactions involve electrons, isotopes have the same number of electrons in the same arrangement

Question 17

What are ions?

Answer 17

Charged particles that are formed when an atom loses or gains electrons

Question 18

What are ions?

Answer 18

Charged particles that are formed when an atom loses or gains electrons

Question 19

What is the charge of the ion when electrons are gained?

Answer 19

Negative e.g 3*+ ion has lost 3 electrons

Question 20

What is the unit used to measure atomic mass?

Answer 20

Unified atomic mass unit, u

Question 21

Define relative atomic mass

Answer 21

The weighted mean mass of an atom of an element compared with one twelfth of the mass of an atom of carbon -12

Question 22

Define relative isotopic mass

Answer 22

The mass of an atom of an isotope compared with one twelfth of the mass of an atom of carbon-12

Question 23

The relative isotopic mass the same as which number?

Answer 23

Mass number

Question 24

What are the uses of mass spectrometry?

Answer 24

•Identify unknown compounds
•Find relative abundance of each isotope of an element
•Determine structural information

Question 25

How does a mass spectrometer work?

Answer 25

•The sample is made into positive ions
•They pass through the apparatus and are separated according to mass to charge ratio
•A computer analyses the data and produces mass spectrum

Question 26

Do metals usually gain or lose electrons?

Answer 26

Lose electrons, non metals usually gain electrons

Question 27

Which 4 elements don’t tend to form ions and why?

Answer 27

Beryllium, boron, carbon and silicon
Because it requires a lot of energy to transfer outer shell electrons

Question 28

What are molecular ions?

Answer 28

Covalently bonded atoms that lose or gain electrons

Question 29

What is the charge of an ammonium ion?

Answer 29

+1 —> NH4+

Question 30

What is the charge of a hydroxide ion?

Answer 30

-1 —> OH*1

Question 31

What is the charge of a nitrate ion?

Answer 31

-1 —> NO3-

Question 32

What is the charge of a carbonate ion?

Answer 32

-2 —> CO32-

Question 33

What is the charge of a sulfate ion?

Answer 33

-2 —> SO42-

Question 34

What is an empirical formula?

Answer 34

Simplest whole number ratio of atoms of each element present in a compound

Question 35

How do you calculate the empirical formula?

Answer 35

1) Divide the amount of each element by its molar mass
2) Divide the answers by the smallest value obtained
3) if there is a decimal, divide by a suitable number to make it into a whole number