Boron is a metalloid, intermediate between metals and non-metals. It exists in many polymorphs (different crystal lattice structures), some more metallic than others. Metallic boron is extremely hard and has a very high melting point.
Explanation:
Hybridization of
is 
Bond pair in
= 2
lone pair in
= 2
Because of presence of two lone pairs of electron shape is bent.
F is more electronegative than O, therefore two O-F bons are polar and hence, two dipole exists. The resultant diople moment in a molecule is the vector sum of individual existing dipoles (shown in the attachment).
because of the bent shape of
two dipole moments add to each other. this result in the existence of permanent dipole moment in the molecule and thus
is a polar molecule.
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Answer:</h3>
Mole ratio of D to A is 1 : 4
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Explanation:</h3>
We are given the generic chemical equation;
4A + B → C + D
We are supposed to determine the mole ratio of D to A
What is mole ratio?
- Mole ratio is the ratio of the number of moles of reactants or products in a chemical reaction.
- We determine the mole ratio using the coefficients of reactants or products in question.
For example;
- In the equation, 4A + B → C + D, the coefficient of A is 4 while the coefficient of D is 1.
- This means, 4 moles of A reacts with 1 mole of b to produce 1 mole of C and 1 mole of D
- Thus, mole ratio of D to A is 1 : 4
Work done by me for using force of 4 N to push an object 3 m away is 12 J.
<u>Explanation:</u>
Work done on any object is defined as the force required to displace that object from its original position. In other terms, the work done is the measure of force utilized for moving an object. So mathematically it is represented as the product of force with the displacement of the object due to that force.

Then, here it is given that force of about 4 N is used to displace the object to 3m. Thus,

So, 12 J of work is done by me to push an object 3 m away with the force of 4 N.
The mass number goes on top, and the atomic number goes on bottom.
Therefore, the answer is C:
40
K
19