Answer: The element shown in the image is Helium (He).
Explanation: We are given a image of an atom having protons, neutrons and electrons.
Number of protons as shown in image = 2
Number of neutrons as shown in image = 2
Number of electron as shown in image = 2
Atomic number = Number of protons = Number of electrons
Atomic number of the element = 2
Atomic Mass = Number of protons + Number of neutrons
Atomic mass = 2 + 2 = 4
The element having Atomic number = 2 and mass number = 4 is Helium.
Element = 
You that Mg is the metal if in the periodic table it lands between group 1-12. So yeas Mg is a metal because it lands in group 2.
The following statements from the paragraph are true. Protons have a mass that contributes significantly to the mass of the atomic nucleus. Neutrons have a mass that contributes significantly to the mass of the atomic nucleus. Electrons have a very low mass and are not found in the nucleus but instead are found in surrounding orbits.