Please help asap!! will give brainliest if right. A student listed the characteristics of chemical and nuclear reactions.

Chemical and Nuclear Reactions:

X - Changes the identity of the element

Y - Does not change the identity of the element

Which of these statements best explains the identity of Reaction X?

It is a nuclear reaction because the identity of elements changes when there is a change in the number of protons and neutrons.

It is a chemical reaction because the identity of elements change when there is a change in the mass of the atoms involved.

It is a chemical reaction because the identity of elements change when there is a change in the overall energy of the system.

It is a nuclear reaction because the identity of elements change when there is a change in the number of outermost electrons.

1st answer is right

Explanation:

nuclear reaction takes place when number of proton or neutron changes in a nucleus forming new products

for eg uranium goes nuclear reaction and gives thorium

- 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