Question

For question #12, use the following picture:

12. What element is this? How do you know?

(the link of the image is down)

goo.gl/DsMGQs

Answer 1

There is a Helium in the picture. It is shown that an atom has two electrons colored by yellow, two protons (red circles in the centre) and two neutrons (green uncharged circles). To conclude, it’s the Helium ‘cause the atomic number of the Helium is 2 (it corresponds to a number of electrons) and the standard atomic weight of the Helium is 4 (the sum number of protons and neutrons an atom has).