Answer:
The atomic number is the number of the elements inside the periodic table and the mass is the weight or a number under the elements.
Explanation:
Correct me if I am wrong
Energy Levels of Electrons. As you may remember from chemistry, an atom consists of electrons orbiting around a nucleus. ... They are restricted to orbits with only certain energies. Electrons can jump from one energy level to another, but they can never have orbits with energies other than the allowed energy levels.
Rocks charcoal and sand could help
Answer:
a) a0 was 46.2 grams
b) It will take 259 years
c) The fossil is 1845 years old
Explanation:
<em>An unknown radioactive substance has a half-life of 3.20hours . If 46.2g of the substance is currently present, what mass A0 was present 8.00 hours ago?</em>
A = A0 * (1/2)^(t/h)
⇒ with A = the final amount = 46.2 grams
⇒ A0 = the original amount
⇒ t = time = 8 hours
⇒ h = half-life time = 3.2 hours
46.2 = Ao*(1/2)^(8/3.2)
Ao = 261.35 grams
<em>Americium-241 is used in some smoke detectors. It is an alpha emitter with a half-life of 432 years. How long will it take in years for 34.0% of an Am-241 sample to decay?</em>
t = (ln(0.66))-0.693) * 432 = 259 years
It will take 259 years
<em>A fossil was analyzed and determined to have a carbon-14 level that is 80% that of living organisms. The half-life of C-14 is 5730 years. How old is the fossil?</em>
<em />
t = (ln(0.80))-0.693) * 5730 = 1845
The fossil is 1845 years old
<span>because p6 will be the group 8. You have to count the 2 electrons from the "s" block that are Group I and Group II
Group I s1
Group II s2
Group III s2 p1
Group IV s2 p2
Group V s2 p3
Group VI s2 p4
Group VII s2 p5
Group VIII s2 p6</span>
