The requirements of atoms to be able to participate in hydrogen bonding with a hydrogen atom include all of the following except a. atoms must have one lone pair of electrons. b. atoms must be electronegative. c. atoms must be small. d. atoms must not be able to closely approach the hydrogen.

 C. atoms must be small.

Explanation:  Hydrogen bond is the result of the electrostatic forces of attraction between the hydrogen and the electonegative atom. It is a type of dipole dipole interaction which is not so much of a covalent bond.

The options A, B and D satisfies the definition of the hydrogen bonding but the option C seems to be irrelevant as hydrogen bonding does not deal with the size of the atom.

Thus for the hydrogen bonding , the other atom must be electronegative, and atoms must have atleast one lone pair of electrons and atoms must not be able to closely approach the hydrogen.

explanation:

metals have excess of electrons whereas non-metals have deficiency of electrons. thus, in order to gain stability metals easily donate their electrons to the non-metals.

for example, electronic configuration of sodium is and electronic configuration of phosphorous is .

when a phosphorous atom and sodium atom combine together then sodium will donate is extra one electron to the phosphorous atom. as a result there will be formation of ionic bond between sodium and phosphorous.

the reaction will be as follows.

there, are three sodium sodium atoms and each of them will donate its one extra electron to phosphorous atom. thus, the sub-shell of phosphorous gets completely filled.  

thus, we can conclude that electrons are transferred from atoms of sodium to atoms of phosphorous. this transfer makes the sodium atoms donate one electron and the phosphorous atoms to gain one electron. as a result, the sodium and phosphorus atoms strongly attract each other.