C is becsuse it just souds right
Answer:
Explanation:
A gives off a visible gaseous product when the two are mixed.
The others all talk about physical properties like phase changes and densities.
Answer:
X has 9 Electrons, 9 Protons and 10 Neutrons
X is Fluorine
Explanation:
19 in X is Nucleon number
So, if you minus 19 by 9 down there (which is proton number) you'll get 10 (Neutron number).
Now, Proton = Electron. That's why Electron is 9 too. I figured that X is Fluorine bcuz it has 9 Electrons. If you venture around in the periodic table, fluorine is the ninth element innit.
hope this helps ya ＼(^o^)／
