Aneutral atom of tin (z = 50) has 69 neutrons. (a) how many protons does it have? (b) what is its mass number?

Protons = 50

Mass number = 119

Explanation:

A neutral of tin, Sn, has a Z value of 50 and neutrons are 69.

Z is the atomic number. The atomic number is equal to number of protons or number of electrons in an atom that is neutral i.e:

Z = PROTONS = ELECTRONS

So the number of protons = 50 since Z is 50

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The bulk of the mass of an atom is concentrated in the nucleus. To calculate mass number, we simply sum all the elementary particles in the nucleus i.e protons and neutrons. These particles are called the nucleons.

Mass number (A) = P + N

= 50 + 69

= 119

absorption lines are where light has been absorbed by the atom thus you see a dip in the spectrum whereas.

emission spectra have spikes in the spectra due to atoms releasing photons at those wavelengths.

explanation:

at positions a, g kinetic energy is maximum.

at position d, potential energy is maximum.