Answer:
42 19 K→42 20 Ca+e−
Explanation:
Naturally-occurring potassium atoms have a weighted average atomic mass of 39.10 (as seen on most modern versions of the periodic table.) Each potassium atom contains 19 protons p+ and thus an average potassium atom contains about 39.10−19≈20 neutrons n0.
This particular isotope of potassium-42 contains 42 nucleons (i.e., protons and neutrons, combined;) Like other isotopes of potassium 19 out of these nucleons are protons; the rest 42−19=23 are therefore neutrons.
A pi bond... hope this helps!!!!!
Answer : The temperature in degree Celsius is, 
Explanation :
The conversion used for the temperature from Kelvin to degree Celsius is:
where,
= temperature in Kelvin
= temperature in centigrade
As we are given the temperature in Kelvin is, 2.7
Now we have to determine the temperature in Kelvin.
Therefore, the temperature in degree Celsius is,
the number of protons in the atomic nucleus
