Answer: C) number of protons
Answer: 1. C. polar covalent: electrons shared between silicon and sulfur but attracted more to the sulfur
2. B) 
3. B) Fluorine
Explanation:
1. A polar covalent bond is defined as the bond which is formed when there is a difference of electronegativities between the atoms.
Electronegativity difference = electronegativity of sulphur- electronegativity of silicon = 2.5 -1.8 = 0.7
Thus as electronegativity difference is less than 1.7 , the cond is polar covalent and as electronegativity of sulphur is more , the electrons will be more towards sulphur.
2. A molecular compound is usually composed of two or more nonmetal elements. Example:
Ionic compound is formed by the transfer of electrons from metals to non metals. Example: 
, 
and 
3. For formation of a neutral ionic compound, the charges on cation and anion must be balanced. The cation is formed by loss of electrons by metals and anions are formed by gain of electrons by non metals.
Here K is having an oxidation state of +1 and as the compound formed is KZ, the oxidation state of non metallic element Z should be -1. Thus the element Z is flourine which exists as diatomic gas 
Answer:
35Cl ⇒ 34.968853 amu has an abundance of 30.05%
Explanation:
The molar mass of chlorine, (which is the average of all its naturally stable isotope masses), is 36.36575 amu.
There are 2 naturally stable isotopes, this means together they have an abundance of 100%
The isotopes are:
35Cl ⇒ 34.968853 amu has an abundance of X %
37Cl ⇒ 36.965903 amu has an abundance of Y %
X + Y = 100% OR X = 100% - Y
36.36575 = 34.968853X + 36.965903Y
36.36575 = 34.968853(1-Y) + 36.936.96590365903Y
36.36575 = 34.968853 -34.968853Y + 36.965903Y
1.396897 = 1.99705Y
Y = 0.699 = 69.95%
X = 100-69.9 = 30.05%
To control, we can plug in the following equation:
34.968853 * 0.3005 + 36.965903 * 0.6995 = 36.3658
This means
37Cl ⇒ 36.965903 amu has an abundance of 69.95 %
35Cl ⇒ 34.968853 amu has an abundance of 30.05%
The reaction of iron sulfide (FeS) with hydrochloric acid (HCl) results in the formation of ferrous chloride (FeCl2) and hydrogen sulfide (H2S) gas. The reaction can be shown as follows:
FeS (s) + HCl(aq) ---- FeCl2(s) + H2S(g)
The bubbles indicate the formation of H2S gas which is a chemical change. The formation of bubbles indicates this change as it suggests that the reactants are combing to form products i.e. it signals a chemical reaction.
The given blank can be filled with isomers.
The isomers in chemistry refers to the molecules or ions with similar formulas, but different compositions. The isomers refer to the molecules that exhibit the same chemical formula, however, distinct three-dimensional shapes. Though isomers do not always share identical properties. The two prime forms of isomerism are stereoisomerism or spatial isomerism and structural isomerism or constitutional isomerism.
