Arrange the elements in each set in order of decreasing electronegativity (enter with no spaces e. g. N>P>Si):

I. N>P>Si N, P, Si
II. As>Ga>Ca Ca, Ga, As
III. Cl>Br>P Br, Cl, P IV. F>O>I I ,F, O

Explanation:

The trend of electronegativity in the periodic table is given as;

The electronegativity of atoms increases as you move from left to right across a period in the periodic table. The electronegativity of atoms decreases as you move from top to bottom down a group in the periodic table.

I. N, P, Si

N is in period 2 while P and Si are both in period 3. N has the greatest electronegativity aamong the three. Since electronegativity increases from left to right in a period, P has a greater electronegativity than Si. The trend is given as; N>P>Si

II. Ca, Ga, As

Since electronegativity increases from left to right in a period, As has the highest electronegativity because it is in group 5 period 4, followed by Ga which is in group 3 period 5, then the least which is Calcium present in group 2, period 5. The trend is given as; As>Ga>Ca

III. Br, Cl, P

Since electronegativity increases from left to right in a period, Cl has the highest value. Bromine has a higher value of electronegativity because it is a group 7 element. The least electronegative is P. The trend is given as; Cl>Br>P

IV. I ,F,O

Fluorine is the most electronegative element. Followed by oxygen. The electronegativity of atoms decreases as you move from top to bottom down a group in the periodic table. The least is Iodine, the trend is given as;   F>O>I

- calcium has greater affinity to bond with electron receptors than hydrogen does and hence, it has the ability to replace hydrogen in most of its compounds.

- lithium has 2 valence electrons in the product because it can make only 1 bond with hydrogen. beryllium has 4 valence electrons in the product because it can only make 2 bonds. it has fewer electrons than neon and can react with electron donors. each hydrogen has 2 valence electrons, the same as helium.

- the covalent bond formed between carbon and hydrogen is polar because carbon is more electronegative than hydrogen and it attracts the bonded electron pair closer to itself, thus giving hydrogen a partial positive charge.

- a hydrogen bond is a relatively weak bond that hydrogen atoms make with the electronegative atoms nitrogen, oxygen or fluorine.

so the best choice is a.) 2 calcium (ca) atoms