Answer: Electronegativity increases as the size of an atom decrease.
Explanation: Electronegativity is the measure of the ability of an atom in a bond to attract electrons to itself.
Electronegativity increases across a period and decreases down a group.
Towards the left of the table, valence shells are less than half full, so these atoms (metals) tend
to lose electrons and have low electronegativity. Towards the right of the table, valence shells are more than half full, so these atoms (nonmetals) tend to gain electrons and have high electronegativity.
Down a group, the number of energy levels (n) increases, and so does the distance between the nucleus and the outermost orbital. The increased distance and the increased shielding weaken the nuclear attraction, and so an atom can’t attract electrons as strongly.
Answer: For the elementary reaction 
the molecularity of the reaction is 2, and the rate law is rate = ![k[NO_3]^1[CO]^1](https://tex.z-dn.net/?f=k%5BNO_3%5D%5E1%5BCO%5D%5E1)
Explanation:
Order of the reaction is defined as the sum of the concentration of terms on which the rate of the reaction actually depends. It is the sum of the exponents of the molar concentration in the rate law expression.
Elementary reactions are defined as the reactions for which the order of the reaction is same as its molecularity and order with respect to each reactant is equal to its stoichiometric coefficient as represented in the balanced chemical reaction.
Molecularity of the reaction is defined as the number of atoms, ions or molecules that must colloid with one another simultaneously so as to result into a chemical reaction. Thus it can never be fractional.
For elementary reaction , molecularity is 2 and rate law is ![rate=k[NO_3]^1[CO]^1](https://tex.z-dn.net/?f=rate%3Dk%5BNO_3%5D%5E1%5BCO%5D%5E1)
Answer: a: reactants Na-2 Cl-2
Products: Na-2 Cl-2;
b: reactants P-1 Cl-13 H-6 Products P-1 H-6 Cl-13
c: reactants P-4 H-12 O-16
Products H-12 P-4 O-16
Explanation: since these equations are balanced the atoms on of element on the reactants side will be same as the atoms of the same element of the product side
Protons= 12, Electrons= 12, neutrons= 12
