Abel observed in his practical lab class that the temperature does not change as long as water boils. Explain this observation giving suitable reasons. b) Phosphorus melts at 44 0 C but lead melts at 325 0 C. Account for this difference in melting points.
c) Ice at 273K is more effective in cooling soft drink bottles than water at 273K. Steam at 373K causes more severe burns than water at 373K.

- 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

i think it is true since you can test the answer and can use observations to complete it.