Atomic Structure

Question 1

define the term atomic number of an element?

Answer 1

the number of protons in the nucleus of an atom

Question 2

define the term mass number of an element?

Answer 2

the total number of protons and neutrons in the nucleus of an atom

Question 3

what is the definition of an isotope?

Answer 3

atoms of the same element with the same number of protons, but different numbers of neutrons

Question 4

what is the relative mass of a proton?

Answer 4

1

Question 5

what is the relative mass of a neutron?

Answer 5

1

Question 6

what is the relative mass of an electron?

Answer 6

1/1840

Question 7

what is the relative charge of a proton?

Answer 7

+1

Question 8

what is the relative charge of a neutron?

Answer 8

0

Question 9

what is the relative charge of an electron?

Answer 9

-1

Question 10

what forces holds together protons and electrons?

Answer 10

electrostatic forces

Question 11

what are the 4 stages of the mass spectrometer?

Answer 11

ionisation, acceleration, deflection + detection

Question 12

write an equation to show the process that occurs when the second ionisation energy of aluminium is measured?

Answer 12

Al+(g) → Al2+(g) + e−

Question 13

state and explain the general trend in first ionisation energies for the period 3 elements aluminium to argon?

Answer 13

increases

the nuclear charge increases whilst the amount of shielding remains the same

Question 14

what is used to ionise a gaseous sample in a mass spectrometer

Answer 14

an electron gun

Question 15

state and explain the difference, if any, between the chemical properties of the isotopes 113In and 115In

Answer 15

none

they have the same electron configuration

Question 16

what is meant by the term first ionisation energy?

Answer 16

energy required for the removal of one electron from a gaseous atom

Question 17

in a mass spectrometer, why is it necessary to ionise atoms before acceleration?

Answer 17

if the particles are not charged they cannot be attracted to and accelerated by a charged plate

Question 18

what is adjusted in order to direct ions of different mass to charge ratio onto the detector?

Answer 18

the strength of the magnetic field

Question 19

what is used in a mass spectrometer to accelerate the positive ions?

Answer 19

a charged plate

Question 20

how are ions detected in a mass spectrometer?

Answer 20

when the positive ions collide with the detector, they accept an electron which generates an electrical current.

Question 21

identify the block in the periodic table to which magnesium belongs?

Answer 21

s block

Question 22

explain why atoms of an element may have different mass numbers?

Answer 22

they may have different numbers of neutrons

Question 23

write an equation, including state symbols, to show the process that occurs when the first ionisation energy of rubidium is measured?

Answer 23

Rb(g) → Rb+(g) + e−

Question 24

state the meaning of the term mass number of an isotope?

Answer 24

the total number of protons and neutrons in the nucleus of an atom

Question 25

state the two measurements that are recorded for each isotope on the mass spectrum?

Answer 25

its m/z ratio and relative abundance