. A sample of Strontium-90 has a Half-Life of 28.1 years. How long will it take for a sample to decay to 12.5% of its original mass?
A sample of Ge-66 (Half-Life = 2.5 hours) sat for 10 hours and only 5 grams remain. What wog
the mass of the original sample?
w
Element X is a Radioisotope. If a 100-kg sample of Element X decays to 12.5 kg in 1 day, what
is the Half-Life of Element X in hours?
Strontium-90 (Half Life = 28.1 years) is used as a Radioactive Tracer in Medical and Agricultural
Studies. How many atoms out of a 1.68 x 1023 atom sample will remain undecayed after 56.2
years?
What percentage of a 900-gram sample of Potassium-37 (Half-Life = 1.23 seconds) exists after
6.15 seconds?

- 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

can you list the answers so i can answer