The number of neutrons in an atom of an element with a relative atomic mass of 55 is 5 units greater

The number of neutrons in an atom of an element with a relative atomic mass of 55 is 5 units greater than the number of protons. Determine the period and group where this element is located.

Any atom consists of a nucleus and electrons revolving around it. The nucleus is made up of protons and neutrons. Moreover, in the ground state of the atom, the number of protons is equal to the number of electrons. Because the mass of an electron is much less than the mass of a proton or neutron, then the relative mass of the atom is also calculated from the nucleus. Conventionally, one unit of mass corresponds to one neutron or proton. Thus, the sum of protons and neutrons corresponds to the relative atomic mass of the atom.

In the periodic table, the numbers of the elements correspond to the number of electrons in the atom and the number of protons in the nucleus.

To calculate the number of neutrons in the nucleus of an unknown element, you can draw up an equation with one unknown. Let the number of protons be X, then the number of neutrons is (X + 5). Their total number is 55. We got the equation:

1 * x + 1 * (x + 5) = 55

x + x + 5 = 55

2x = 55 – 5

2x = 50

x = 50: 2

x = 25

It turns out that the number of protons = 25, which means both the number of electrons = 25 and the serial number = 25.

At number 25 in the periodic table is Manganese – Mn. Period 4, group VII, side subgroup.