Which statement about the relationship between laws, hypotheses, and theories is true? a. laws that remain true over an extended period of time are considered theories. b. a theory that holds true for a long time is considered a law. c. if a law is not contradicted after a lot of testing, it may be considered a hypothesis. d. if a hypothesis is not contradicted after a lot of testing, it may be considered a law.

D. If a hypothesis is not contradicted after a lot of testing, it may be considered a law.

- 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