Atomic Structure and Periodic Table

Question 1

Isotopes

Answer 1

Atoms with the same number of protons, but a different number of neutrons

Question 2

Relative isotopic mass

Answer 2

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

Question 3

Describe the properties of isotopes

Answer 3

• similar chemical properties (same electronic structure)

* slightly varying physical properties (different masses)

Question 4

Relative atomic mass

Answer 4

Average mass of one atom compared to one twelfth of the mass of one atom of carbon-12

Question 5

Relative molecular mass

Answer 5

The average mass of a molecule compared to one twelfth of the mass of one atom of carbon-12

Question 6

What is the relative mass of an electron

Answer 6

1/1840

Question 7

Describe the nucleus

Answer 7

• carries virtually all the mass of an atom

* positively charged

Question 8

How is the chemical nature of an atom determined?

Answer 8

Through how many electrons it has and their arrangement

Question 9

Relative formula mass

Answer 9

• relative molecular mass but for ionic compounds (not molecules) and giant covalent molecules (because the size of the molecule varies, so it cannot have a precise molecular mass)
• used for compounds with giant structures

Question 10

What is microscopy used for?

Answer 10

To determine all of the isotopes present in a sample of an element
(the identification of elements)

Question 11

Describe the process of mass spectrometry

Answer 11

1) the same is vaporised
2) the same is ionised
3) the ions is accelerated through an electric field
4) the ions is deflected through a magnetic field
5) the ions are detected and recorded

Question 12

Describe the process of ionisation

Answer 12

• the valorised sample is fed into the ionisation chamber
• it is bombarded by a stream of high-energy electrons fired from an electron gun
• electrons are knocked out of molecules in the sample

Question 13

Describe defection

Answer 13

Depends on the mass and charge of the ions

Question 14

Lower mass

Answer 14

Deflected too much

Question 15

Higher masses

Answer 15

Deflected too little

Question 16

Define first ionisation energy

Answer 16

The energy required to remove one electron from each atom in one mole of gaseous atoms to produce one mole of gaseous ions with a 1+ charge

Question 17

What does first ionisation energy do?

Answer 17

Provides information about the attraction between the nucleus and the outer-shell electrons

Question 18

What does the attraction of an outer shell electron to the nucleus depend on?

Answer 18

• nuclear charge -> the amount of protons relative to the amount of neutrons; higher the charge, greater the attraction
• the distance from the nucleus; greater the distance, smaller the attraction
• shoidelding -> the more inner electrons, the smaller the attraction

Question 19

Describe the trend in first ionisation energy across a period

Answer 19

• increase
• electrons are added to the same electron shell, the same distance from the nucleus
• nuclear charge increases
• more eneergy is needed

Therefore, group 1 has the lowest and group 8 has the highest

Question 20

Describe the trend in first ionisation energy down a group

Answer 20

• decreases
• distance increases
• greater shielding