Electronegativity

Question 1

What is electronegativity

Answer 1

Electronegativity is a atoms power to attract electron density in a covalent bond towards itself

Question 2

When chemists
consider electron charge clouds the word ….. is used to describe the way negative charged is distributed in a molecule

Answer 2

density

Question 3

What is the scale used for electronegativity

Answer 3

Pauline scale 0-4

The greater the number the more electronegative the atom

Question 4

What groups have no electronegative value and why

Answer 4

Noble gases they don’t form covalent bonds

Question 5

Electronegativity depends on

Answer 5

Nuclear charge

the distance from nucleus to outer shell electrons

shielding of the nuclear charge by electrons

Question 6

electro negativity trend

Answer 6

Smaller the atom the closer the nucleus to the shared outer shell electron the stronger the charge

The larger the nuclear charge , the greater the electronegativity

Up the group it increases due to atoms getting smaller greater attraction from nucleus

Going across the table electronegativity gets stronger the nuclear charge(for a given shielding effect|) increases , the number of inner layers is the same and atoms become smaller

Question 7

What are the most electronegative elements

Answer 7

top right except noble gases fluorine , oxygen and nitrogen followed by chlorine

Question 8

What is polarity

Answer 8

Is about unequal sharing of electrons between atoms that are bonded covalently

Question 9

Covalent bonds that have the same electronegative forces are called

Answer 9

non-polar charge is uniformly spread

Question 10

what does (δ)+(delta plus ) and (δ)-(delta minus ) mean

Answer 10

the + and - signs represent one electrons charge

the delta δ means a small charge worth less than one electrons worth

Question 11

example δ+h - f δ-

Answer 11

Hydrogen end is said to be relatively positive is electron deficient

Fluoride said to be relatively negative electron cloud distorted fluorides way

Question 12

why is electronegatitivity affected by nuclear charge

Answer 12

Attraction exists between the positively charged protons in the nucleus and negatively charged electrons found in the energy levels of an atom

An increase in the number of protons leads to an increase in nuclear attraction for the electrons in the outer shells

Therefore, an increased nuclear charge results in an increased electronegativity

Question 13

Why is electronegativity affected by electron shielding

Answer 13

Filled energy levels can shield (mask) the effect of the nuclear charge causing the outer electrons to be less attracted to the nucleus

Therefore, the addition of extra shells and subshells in an atom will cause the outer electrons to experience less of the attractive force of the nucleus
Sodium (period 3, group 1) has higher electronegativity than caesium (period 6, group 1) as it has fewer shells and therefore the outer electrons experience less shielding than in caesium

Thus, an increased number of inner shells and subshells will result in a decreased electronegativity

Question 14

Why is electronegativity affected by the atomic radius

Answer 14

The atomic radius is the distance between the nucleus and electrons in the outermost shell

Electrons closer to the nucleus are more strongly attracted towards its positive nucleus

Those electrons further away from the nucleus are less strongly attracted towards the nucleus

Therefore, an increased atomic radius results in a decreased electronegativity

Question 15

electronegativity trend for groups

Answer 15

Down a group

There is a decrease in electronegativity going down the group

The nuclear charge increases as more protons are being added to the nucleus
However, each element has an extra filled electron shell, which increases shielding

The addition of the extra shells increases the distance between the nucleus and the outer electrons resulting in larger atomic radii

Overall, there is decrease in attraction between the nucleus and outer bonding electrons

Question 16

Going across period electronegativity trend

Answer 16

Across a period

Electronegativity increases across a period

The nuclear charge increases with the addition of protons to the nucleus
Shielding remains relatively constant across the period as no new shells are being added to the atoms

The nucleus has an increasingly strong attraction for the bonding pair of electrons of atoms across the period of the periodic table

This results in smaller atomic radii