Answer: The bond between boron and hydrogen in boron trihydride is covalent bond.
Explanation:
The type of bonding between the atoms forming a compound is determined by using the electronegativity difference between the atoms. According to the pauling's electronegativity rule:
- If
, then the bond is non-polar. - If
, then the bond will be covalent. - If
, then the bond will be ionic.
We are given:
Electronegativity for boron = 2.0
Electronegativity for hydrogen = 2.1

As,
is less than 1.7 and not equal to 0. Hence, the bond between boron and hydrogen is covalent bond.
Answer:
There are 1000 mg in 1. g
There are 1000 g in 1 kg
Each students needs 2,250 mg of clay
Explanation:
In order to determine the amount of how many kilograms to order, the teacher will need to find out the total mass of clay required by the students and then the teacher will have to convert the total mass to the units required for the purchase.
The teacher would have to find out how many milligrams make one kilogram as follows
1 kg = 1000 g
1 g = 1000 mg
Therefore, 2,250 mg = 2250/1000 g = 2.25 g
2.25 g = 2.25/1000 kg = 0.00225 kg.