Atomic structure and isotopes

Question 1

what is an atom?

*include all key parts

Answer 1

the smallest part of an element which can react in a chemical change

Question 2

describe the structure of an atom

Answer 2

1- small dense nucleus in the center consisting of proton and neutrons
2- in shells around the nucleus, electrons are found

Question 3

what is atom mostly of?

Answer 3

empty space

Question 4

what are the relative charge of protons, neutrons and electrons?

Answer 4

proton=+1
neutron=0
electron=-1

Question 5

what are the relative masses of protons, neutrons and electrons?

Answer 5

proton=1
neutron=1
electron=1/1836

Question 6

describe a nuclear notation(what each letter as the example mean)

• use the scientific terms
  eg: vCx

Answer 6

v-mass number/nucleon number( number of proton and neutrons )
C- symbol of the element
x-atomic number/ proton number

Question 7

what is the mass number actually?

Answer 7

number of protons and neutrons in the nucleus of an atom

-number of total mass of parts in the element but electrons are so small so they are not considered in the calculations

Question 8

What is relative atomic mass

Answer 8

The average mass of all the isotopes of the same element when compared to carbon-12

Question 9

What is the formula to calculate relative atomic mass using percentage abundance of isotopes?

Answer 9

Percentage 1(mass number1)+ percentage 2(mass number 2) / percentage 1 + percentage 2

Question 10

what does K+1 mean?

Answer 10

the potassium ion as one less electrons than proton or one more proton then electron

Question 11

what does k-3 mean?

Answer 11

potassium has gained 3 electrons

Question 12

describe how electron beams react in an electrical field

*cathode ray tube

Answer 12

1- electrons get repelled from the cathode and attracted to the anode
2- the electron deflects towards the positive plate and hit one certain area of the screen making it glow

Question 13

what is an alpha particle?

Answer 13

helium ion with 0 electrons and therefore acts as a proton

Question 14

describe how alpha particles react in the gold foil experiment
*2 main answers and explanation

Answer 14

1- alpha particles travel straight and un-deflected as atom is mostly empty space
2- some alpha particles are deflected as a result of
a) repulsion of positive charge of nucleus
b) the nucleus is tightly packed

Question 15

describe how neutrons react in an electrical field

Answer 15

they travel straight, un-deflected due to no charge

Question 16

what is effective nuclear charge?

Answer 16

the amount of positive charge felt by electrons in the last shell taking into consideration the shielding effect

Question 17

how does atomic radius change across a period

and explain

Answer 17

the atomic radius decreases.
As the number of protons increases, the effective nuclear charge of electrons in the last shell increases causing an attraction between the electrons and the nucleus.

Question 18

how does atomic radius change down the group?

Answer 18

atomic radius increases
The number of protons down the group increases causing electrons to increase too. due to this, there will be more electron shells/energy level, making the atom get bigger

Question 19

what do elements in the group have the same of related to this topic?

Answer 19

same number of outer electrons therefore same effective nuclear charge which is why nuclear charge is not considered when talking about elements of the same group

Question 20

what are anions and cations

Answer 20

cations-positive ions

anions- negative ions

Question 21

how do cations change across the period ?

and explain

Answer 21

they decrease across a period, cations lose electrons leading to greater positive charge across the period causing the effective nuclear charge to increase so more attraction between the electrons and nucleus
* the greater the positive charge, the smaller the radius

Question 22

how cations change down a group?

and explain

Answer 22

they increase down the group as the energy level/ electron shell increases however nuclear energy remains the same

Question 23

explain how anions differ from their natural element

Answer 23

they are bigger than their elements because they have more electrons therefore more repulsion between one another. nuclear energy is not taken into consideration as they have the same nuclear charge

Question 24

explain how anions radius change down the group?

Answer 24

they increase down the group as the electron shell increases causing more repulsion between electrons

Question 25

explain how anions radius change across the period?

Answer 25

across the period, the anions decreases in size as the proton number increases so nuclear charge increase

Question 26

how does nuclear charge change down a group and across a period

Answer 26

down a group= same nuclear charge

across a period= nuclear charge increases

Question 27

how does electron shell change down a group and across a period

Answer 27

down the group= electron shell increases

across a period= electron shell remains the same

Question 28

what is an isotope

Answer 28

atoms of the same element with different number of neutrons and same number of protons

Question 29

what are 2 similarities of isotopes of the same element?

Answer 29

1- same number of protons

2- same chemical properties

Question 30

what are 3 differences of isotopes of the same element?

Answer 30

1- different physical properties
2- different mass number/nucleon number
3- different neutron number

Question 31

what exactly determines isotopes of an element having the same chemical property
*include electrons and stability

Answer 31

the number of electrons in its outer shell as they may need to gain or lose the same number of electrons to become stable

Question 32

explain why isotopes of the same element have the same chemical properties

Answer 32

isotopes of the same element have the same number of electrons causing the electronic configuration to be the same as well as the number of valence electrons which determines the chemical properties.

Question 33

why do isotopes of the same element have different physical property?

Answer 33

isotopes of the same elements, have different mass numbers. given by the equation density=mass/volume, a different mass leads to different densities.

Question 34

what factor exactly determines the physical property of isotopes?

Answer 34

its density. Different density leads to different physical property

Question 35

what is true of isotopes abundance?

Answer 35

all isotopes of the same elements exist in different abundances