Using this model of a helium atom, what is the atomic number and mass number?

1 Answer
anor277
Feb 2, 2017

Using the standard model of the helium atom..........

Explanation:

Using the standard model of the helium atom, #Z=2#; that is there are 2 protons, 2 massive positively charged particles in the helium nucleus, and #Z="the atomic number"=2#. Because helium is a NEUTRAL entity (most matter is!), associated with the atom there are 2 electrons, conceived to whizz about the nucleus. Also contained in the helium nucleus, there are 2 neutrally charged #"neutrons"#, which are massive particles of neutral charge. And thus we represent the helium atom as #""^4He#. Why don't we have to specify the #"atomic number"# in this label?

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