Trends In PTE

Question 1

What is Atomic Radius

from top to bottom, atomic radius ____

L–>R, atomic radius _____

Answer 1

As u move from top to bottom, atomic radius INCREASES because another energy level is added

L–>R, atomic radius DECREASES because of the inxrease in positive charge of the nucleus. This creates a stronger force of attraction between the electrons and nucleus, resulting in a smaller atomic Radius.

Question 2

What group has the smallest atoms in their respective period?

Answer 2

The noble gases

Question 3

What is Ionic radius

Describe it

Answer 3

Size of an atom when the atom gains (anion) an electron or loses an electron (cation)

+ve ions are always SMALLER than their corresponding neutral atom because a valence electron was removed. Force is shared among fewer electrons creating a stronger force of attraction between the nucleus and electrons. Loses valence electrons–>valence shell removed

-ve ions are BIGGER than their neutral atom. This is because there’s a stronger force of repulsion between electrons, causing them to spread apart. The nucleus can’t hold them so close together anymore, resulting in larger atomic Radius.

Question 4

What is ionization energy

Answer 4

Energy required to remove an electron from an atom.
Increases moving L-->R
--------->
|
|  decreases from top-->bottom
☆

Question 5

Why does ionization energy ____ from L–>R

Answer 5

ionization energy INCREASES from L–>R because:

1. there’s a stronger attraction to the positively charged nucleus. This requires more energy to break this bond, hence why there’s an increase in ionization energy.
2. The atomic Radius is smaller so electrons are closer to the nucleus, making it more difficult to break the bond of attraction between them

Question 6

Why does ionization energy ____ from top to bottom

Answer 6

Ionization energy DECREASES from top to bottom because:

1. There are more energy levels added on so there’s an increase in distance between the valence electrons and the positively charged nucleus. Less energy is required to remove the valence electron from the atom

Question 7

What is electronegativity

Answer 7

The ability of an atom to attract shared pair of electrons in a chemical bond

Question 8

Electronegativity:

___ down a group and ____ across a period from L->R

Answer 8

Yg

Question 8

Electronegativity:

___ down a group and ____ across a period from L->R

Answer 8

Electronegativity DECREASES from top to bottom because as the size of the atom decreases, the valence electrons are closer to the nucleus. It doesn’t take much electronegativity to attract electrons because they’re closer to the nucleus already.

Electronegativity INCREASES from L–>R because there’s a strong positive charge in the nucleus that pulls electrons closer to the nucleus. It requires more energy to pull the electrons away.
The atomic Radius decreases so valence electrons are closer to the nucleus

Question 9

Electronegativity:

___ down a group and ____ across a period from L->R

Answer 9

Electronegativity decreases from top to bottom

Question 10

Atoms with HIGH electronegativities tend to ____ the nucleus

Answer 10

Pull electrons closer/towards

Question 11

Atoms with LOW electronegativities tend to ___ the nucleus

Answer 11

Pull electrons FURTHER AWAY from the nucleus

Question 12

Electronegativity of <0.4

Answer 12

Non polar covalent bond

Question 13

Electronegativity between 0.5

Answer 13

Polar covalent bond

Question 14

EN>1.8

Answer 14

Ionic bond

Question 15

What is electron affinity

Answer 15

Change in energy that occurs when an electron is added to the outer energy level of an atom to form an anion

Question 16

What does a negative electron affinity mean?

Answer 16

Energy is released when an atom gains an electron, likely forming an ANION

Question 17

What does a positive electron affinity mean?

Answer 17

Energy is absorbed when an atom gains an electron, likely forming an anion

Question 18

How does size impact electron affinity

Answer 18

Size increases, its hard for nucleus to pull electrons. The smallest element in a row has the highest EA