To show the electron configuration for an atom when would it be better to use an orbital notation than to use a written configuration with numbers letters and subscripts

It is more convenient to use an orbital diagram when you want to show the number of unpaired electrons.

For example, the electron configuration of N is 1s² 2s²2p³.

The orbital diagram (see image below) gives the same information, but it also shows that the three 2p electrons are unpaired.

The number of unpaired electrons is useful when you are trying  to discover the magnetic properties of an atom or ion.

120,630,890

step-by-step explanation:

110+10=120,620+10=630,880+10=890

- 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