Answer:
Element symbol: Kr.
Mass number: 77.
Charge : 0.
Explanation:
Hello,
In this case, since such substance has the same amount of protons and electrons we can infer it is an atom whose number of neutrons is defined by considering its atomic mass or mass number and atomic number which is actually equal to the number of protons and electrons (36):

In such a way, solving for the atomic mass we obtain:

It means that the element is krypton (Kr) as it has 36 electrons and protons so its charge is 0.
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Answer:
The nucleus consists of 25 protons (red) and 30 neutrons (blue). 25 electrons (green) bind to the nucleus, successively occupying available electron shells (rings). Manganese is a transition metal in group 7, period 4, and the d-block of the periodic table. It has a melting point of 1246 degrees Celsius.
C. Electron. It’s a negatively charged particle that orbits around the nucleus. Usually, there are multiple electrons going around the nucleus in different orbitals (the circle around the nucleus in which the electron travels). The mass is much smaller compared to that of a proton or neutron and can be ignored when calculating the mass of an atom.
5cm
Explanation:
you have to divide 100cm by 20 sec