Topic 3.1

Question 1

What is a molecule?

Answer 1

A molecule is a group of two or more atoms held together by attractive forces known as chemical bonds

Question 2

What does VSEPR stand for?

Answer 2

Valence Shell Electron Pair Repulsion

Question 3

What are electron dense regions and what are bonded/lone pairs?

Answer 3

Regions with electrons. Lone pairs are pairs of electrons that are not bonded. Bonded pairs are pairs that are bonded.

Question 4

How many electron dense regions and lone pairs in a linear shape?

Answer 4

2 and 0

Question 5

What are the shapes that have 3 electron dense regions?

Answer 5

Trigonal planar and bent

Question 6

shape that has 4 electron dense regions and 0 lone pairs

Answer 6

tetrahedral

Question 7

What are the shapes that have 4 electron dense regions?

Answer 7

tetrahedral, trigonal pyramidal and bent

Question 8

What is the shape of NH3?

Answer 8

trigonal pyramidal

Question 9

What is the shape of BH3?

Answer 9

trigonal planar

Question 10

what is the shape of CO3 2+

Answer 10

trigonal planar

Question 11

State and explain the shape of CH4

Answer 11

The central C atom has 4 electron dense regions. Composed of 4 paired and 0 lone pairs. These regions separate at a maximum distance to minimise repulsion. Tetrahedral shape.

Question 12

State and explain the shape of CO3 2-.

Answer 12

The central C atom has 3 electron dense regions. Composed of 3 bonded pairs and 0 lone pairs. These regions separate at a maximum distance to minimise repulsion. Trigonal planar shaep.

Question 13

Difference between polar and nonpolar molecules

Answer 13

Polar molecules have distinct positive and negative ends, nonpolar ones do not.

Question 14

How are the charges distributed in a polar molecule

Answer 14

unevenly

Question 15

Is a trigonal planar and tetrahedral a nonpolar or polar molecule?

Answer 15

nonpolar

Question 16

Are bent or trigonal pyramidal a nonpolar or polar molecule?

Answer 16

polar

Question 17

Is NH3 polar or nonpolar?

Answer 17

polar

Question 18

is CO2 polar or nonpolar?

Answer 18

nonpolar

Question 19

What is the shape and polarity of H2S?

Answer 19

v-shape and nonpolar

Question 20

What is the shape and polarity of SiH4

Answer 20

tetrahedral and nonpolar

Question 21

State and explain the polarity of SO3.

Answer 21

Atoms of SO3 have unequal electronegativity. Charges are evenly distributed throughout the trigonal planer shaped SO3. SO3 is nonpolar.

Question 22

State and explain the polarity of CH3CL.

Answer 22

Atoms of CH3CL have different elecronegativity. Charges are unevenly distributed throughout the tetrahedral shape. The surrounding atoms around the central C atom are not the same. It is a polar molecule.

Question 23

Is NH3 or PH3 more polar?

Answer 23

NH3 is more polar because there is a bigger difference in electronegativity.