<h3>Further explanation</h3>
1.Atomic Number (Z) = Mass Number (A) - Number of Neutrons
neutrons = mass number-atomic number
Atomic mass Cl-37= 17
Mass number Cl-37=37
Neutrons = 37-17=20
2. Mass atom X = mass isotope 1 . % + mass isotope 2.%...

3. The energy in one photon can be formulated as

f = c / λ, so :

Energy is directly proportional to frequency and inversely proportional to the wavelength
So, as the frequency of photon increases, the energy of photon increases
4. Based on answer number 3 :
A. The wavelength becomes longer, and the energy decreases
Answer:
actually there are 6 of them
Explanation:
heres the list:
They are beryllium, magnesium, calcium, strontium, barium, and radium.
hope it helpssss :)
Answer:
Non-zero digits are always significant
Answer: With atomic number 20, calcium atoms have 20 positive protons, and the ion has only 18 electrons, which means the net charge is +2. Calcium ions are essential for muscle contractions, nerve impulses, and bone maintenance.
:
Answer:
Different isotopes of the same element have the same number of protons in their atomic nuclei but differing numbers of neutrons. Radioisotopes are radioactive isotopes of an element. They can also be defined as atoms that contain an unstable combination of neutrons and protons, or excess energy in their nucleus.