posted by Taylor .
Why do beryllium and fluorine combine in a 1 : 2 Ratio?
Be is in group 2 (or IIA). F is in group VIIA (or 17 depending upon what system you are using). Therefore, flourine needs one electron to fill its outside shell. Be has two in its outside shell to give. So Be gives an electron to each of two F atoms to make BeF2.
why do beryllium and fluorine combine in a 1:2 ratio?