Answer:
Explanation:
A pure substance is made up solely of that substance and can't be separated into any other substances. A mixture can be separated into two or more pure substances
1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p2, valence shell: 4s2 3d10 4p2
Answer: 2948
Explanation:
Half life is the amount of time taken by a radioactive material to decay to half of its original value.
Expression for rate law for first order kinetics is given by:
where,
k = rate constant =
t = age of sample = ?
a = let initial amount of the reactant = 100
a - x = amount left after decay process = 
Thus the fossil is 2948 years old.