It's the same as the number of protons, which is the atomic number. It's the top number of the element box
atomic number
Aluminum is in group III A, which lets you know that it has 3 electrons in its outermost orbital. Hope this helps.
Just so you know, the periodic table does not give any indication of how many electrons an atom has but 95% of sulfur atoms are neutral and so contain 16 electrons.
phosphorus have 15 electron because you know the atomic number to know electron
6 protons 6 neutrons 6 electrons. If you can use Wikianswers then you should know how to use Google
Generally how many protons it has, therefore what type of atom it is (i.e. carbon, hydrogen etc.)
I don't know Se-50.
you see how many electrons and protons it has and add them together
Magnesium is a metal element. There are 12 electrons in a single atom.
Selenium-55 has 34 protons, 21 neutrons, and 34 electrons.
The shell closest to the nucleus of an atom can only hold up to two electrons.
Finding the number of electrons in an atom is easy. You just have to know the atomic number of the element. The atomic number for Potassium is 19. That means Potassium has 19 electrons.