Jai was measuring the radioactivity of different radioactive isotopes. Isotope A had a starting radioactive level of 50 g, and after 4 days it measured at 30 g. Isotope B had a starting radioactive level of 75 g, and after 4 days it measured at 25 g. Which best explains the isotopes? Isotope A has a shorter half-life than Isotope B.
Isotope A has a longer half-life than Isotope B.
Isotope A has half the half-life of Isotope B.
Isotope A has twice the half-life of Isotope B.

Its the second one (B)

Explanation:

Marki the person that answerd first brainliest :)

- 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