Given the following, how many protons are in an atom of chlorine? What is the atomic number of sodium?

Question

An atom of chlorine (Cl) has 6 more protons than an atom of sodium (Na). The atomic number of chlorine is 5 less than twice the atomic number of sodium. The atomic number of an element is equal to the number of protons per atom.

4447 views around the world

You can reuse this answer
Creative Commons License

Answer 1 · 2017-05-14T08:50:28

For #Cl#, #Z=17#.

#Z="the atomic number"#, the number of massive, positively charged nuclear particles. #Z# defines the identity of the element. For #Cl#, #Z=17#.

We are given that #Z_"Na"+6=Z_"Cl"#, and thus #Z_"Na"=11#.

And #2xxZ_"Na"-5=22-5=17=Z_"Cl"# as required.