Answer:
10 neutrons
Explanation:
N=Z-A ie. number of neutrons=mass number-atomic number
N=19-9=10
Answer:
The correct option is;
A) 1 to 1.
Explanation:
A stab;e nuclei requires the presence of a neutron to accommodate the the protons repulsion forces within the nucleus. An increase in the number of protons should be accompanied by an even more instantaneous increase in the number of neutrons to balance the forces in the nucleus. If there is an excess of neutrons or a deficit in protons a state of unbalance exists in the nucleus, which results to nuclear instability.
Therefore, the ratio of neutrons to protons is an appropriate way in foretelling nuclear stability and a stable nuclei is known to have a proton to neutron ratio of 1:1 and the number of protons and neutrons in the stable nuclei are usually even numbers.
Answer:
=7.89013× 10^47 moles of zinc
Explanation:
1 atom contains 6.023×10^23 moles.
1.31×10^24 atoms of zinc contain6.023×10^24×1.31×10^.24
Cs -137 has a half life of about 30 years. If 60 years pass, there is two half lives passed so 1/2 * 1/2= 1/4. Take 1/4 and multiply it with the mass given:
(1/4)*20mg=5mg left
