Periodicity

Question 1

On which side are metals found on the periodic table?

Answer 1

The left side

Question 2

On which side are non-metals found on the periodic table?

Answer 2

The right side

Question 3

Where are metalloids found on the periodic table?

Answer 3

In the middle

Question 4

What do metals tend to lose and form?

Answer 4

Metals tend to lose electrons and form positive ions.

Question 5

What happens when an elements loses an electron?

Answer 5

Its becomes a positively charged cation

Question 6

What happens when an elements gains an electron?

Answer 6

It becomes a negatively charged anion

Question 7

What is electron affinity?

Answer 7

Electron affinity is when an element in gas phase gains an electron and becomes a negative ion. The higher the electron affinity of an element is, the easier it is to form a negative ion.

Question 8

Do non metals, metals, or metalloids have higher Electron affinity?

Answer 8

Non-metals have a higher EA than metals, and tend to form negative ions (Anions)

Question 9

Why is it so difficult for group 7 elements to lose an electron?

Answer 9

because they are very close to have a stable octet but they will readily accept an electron.

Question 10

What does it mean if electron affinity have positive values?

Answer 10

Positive values of electron affinity means that electrons will not attach themselves
to the atoms. In the case of N, the additional electron will have to pair with another
electron in the 2px orbital – larger electron repulsions!

Question 11

Why are Ionisation Energy and Electron Affinity important?

Answer 11

Elements with low ionisation potential easily give their electrons to elements with high electronic affinity. This forms an ionic bond.

Question 12

What happens between two elements if ionisation potential is too high or if electronic affinity is too low?

Answer 12

If the ionisation potential is too high, and / or the electronic affinity is too low,
they don’t bother becoming ions, and prefer to share their electrons and form a
COVALENT BOND

Question 13

What is the periodic table based on?

Answer 13

The periodic table is based on a set of rules common to the elements which is atomic structure.

Question 14

How are elements arranged in the periodic table?

Answer 14

Elements which have similar chemical properties occur in periodic intervals relative to their respective atomic mass, which is why they are arranged the way they are in the periodic table.

Question 15

Which elements have lower ionisation energy?

Answer 15

Elements on the left side of the periodic table (metals) have low ionisation energy. Elements on the right side of the table (non metals) have the highest ionisation energy.

Question 16

What are the vertical rows for?

Answer 16

Groups

Question 17

What are placed in groups?

Answer 17

-Elements with similar properties are place in groups.

Question 18

What are horizontal rows for?

Answer 18

Periods

Question 19

What does period number correspond to?

Answer 19

-Period number corresponds to the highest occupied energy level.

Question 20

What are transition elements?

Answer 20

elements with incomplete d orbitals

Question 21

What are representative elements?

Answer 21

elements with full inner orbitals but an incomplete outer shell.

Question 22

Which electrons are the most reactive?

Answer 22

Valence electrons.

Question 23

How to abbreviate electron configs?

Answer 23

Watch this:
https://www.youtube.com/watch?v=rmu3kA6VS8c

Question 24

How is the periodic table in elongated form arranged

Answer 24

Arranged linearly with respect to atomic number.

Question 25

Why are higher energy levels good?

Answer 25

Higher energy levels (shell) = more space for electrons to fill (atomic radii)
> energy level 4 = space for more electrons (d orbitals)
> energy level 6 = space for even more (f orbitals)

Question 26

Why do elements in the same group have the same valency?

Answer 26

They have the same outer energy level/electron configurations. Therefore they have the same valency.

Question 27

Why is the periodic table useful?

Answer 27

Characteristic properties and trends of the elements allow us to use the periodic table to predict properties and reactions of a variety of substances such as:

• Metals and nonmetals
• Atomic volume
• Ionisation energy
• Electron affinity
• Electronegativity

Question 28

Where are metals found on the periodic table?

Answer 28

The left

Question 29

Where are non metals found on the periodic table?

Answer 29

On the right

Question 30

Why do metals tend to lose electrons?

Answer 30

To form positive ions.

Question 31

What are the chemical properties of metals?

Answer 31

Metals tend to lose e - and form positive ions

Question 32

What the phyisical properties of metals?

Answer 32

▪ lustrous
▪ malleable
▪ good conductors of heat
▪ good conductors of electricity.

Question 33

Chemical properties of non metals?

Answer 33

Non-metals tend to gain e- and form negative ions

Question 34

Physical properties of non metals?

Answer 34

▪ Non-lustrous
▪ brittle
▪ poor conductors of heat
▪ poor conductors of electricity

Question 35

What is transferred to what when metals react with non-metals?

Answer 35

When metals react with nonmetals e - are usually transferred from the metal to the non-metal

Question 36

Properties of metalloids?

Answer 36

Metalloids have properties that are intermediate between metals and nonmetals

Question 37

Metallic character increases as…

Answer 37

Metallic character increases as you go down a group and from right to left. Metals are also more likely to form positive ions as you go left and down.

Question 38

What are the valence electrons attracted to and repelled by?

Answer 38

A valence electron is attracted to the positively charged nucleus, and repelled by other electrons in the atom.

Question 39

What is the function of the inner core electrons in relation to the valence shells attraction to the nucleus?

Answer 39

The inner core electrons are effective at partially cancelling the attraction of the valence electron for the nucleus.

The inner core of electrons screen or shield the valence electrons from the positive nuclear charge of the nucleus.

Question 40

What does the screening factor represent?

Answer 40

The screening factor (S) represents the number of inner core electrons.

Question 41

What does Z represent?

Answer 41

Number of protons

Question 42

Equation for Effective nuclear charge (Zeff)

Answer 42

Effective nuclear charge (Zeff) = Z (num of protons) – S (screening factor (number of inner core electrons) ).

Question 43

Zeff Example: Magnesium.

Answer 43

Electron configuration = 1s2, 2s2, 2p6, 3s2
The 1s2, 2s2, 2p6 are the core electrons. It has 10 of them.
The 3s2 are the valence electrons.
It has 12 protons since atomic number = num of protons = num of electrons
Effective nuclear charge (Zeff) = 12 – 10 = +2
The valence electrons are both subjected to a nuclear force of +2 – each pulled inwards from the strength of 2 protons

Question 44

What are the valence electrons subjected to in Mg?

Answer 44

The valence electrons are both subjected to a nuclear force of +2 – each pulled inwards from the strength of 2 protons

Question 45

What is Effective nuclear charge important for?

Answer 45

Important implication for ionisation energy

Question 46

What is ionisation energy?

Answer 46

Ionisation energy is the energy required to remove an electron from a (valence) shell.

Question 47

Do elements in the same group all have the same configuration?

Answer 47

Yes

Question 48

As we move from one element to another, effective nuclear charge…

Answer 48

increases.

Question 49

Why does nuclear charge of elements increase as we go across the periods?

Answer 49

The additional valence electrons added to counterbalance the nuclear charge shield each other ineffectively, hence effective nuclear charge increases.

Question 50

What are the trends in atomic volume?

Answer 50

Radii of atoms increase down a group
This is due to the quantum (electrons) number increasing (n) i.e.
The outer electrons are further away from the nucleus
Radii of atoms tend to decrease from left to right across a period
Each time an electron is added, a proton is added to the nucleus.
This increases the positive effective nuclear charge (Zeff) which pulls all the electrons closer to the nucleus

Question 51

In general, smaller atoms have…

Answer 51

In general, smaller atoms have higher ionisation energies

Question 52

What does ionisation energy depend on?

Answer 52

IE depends on Zeff and the average distance of the electron from the nucleus

Question 53

What happens when you decrease the distance of the electron from the nucleus?

Answer 53

Decreasing the distance of the electron from the nucleus or increasing Zeff increases ionisation energy.

Question 54

Do metals or non metals have lower IE (ionisation energy)

Answer 54

Metals have lower ionization energies than non-metals, they tend to form positive ions (Cations)

Question 55

Where does IE increase on the periodic table?

Answer 55

Ionisation energy also increases as you go up the groups and across the periods. For example Hydrogen has a higher IE than Lithium, and lithium has a higher IE than Sodium. And Helium has the highest IE of all.