Answer:
Explanation:
1) alkali metals and halogens as alkalis have 1 electron they need to get rid of in order to gain a full outer shell of electrons and the halogens have to gain 1 electron.
2) they have the same number of electrons on the outer shells
3)they usually have high melting points
4) low or no reactivity
5) group 7
The word atom comes from the Greek atomos which means indivisible, indivisible (excepted in the nuclear reactions). It was therefore perfectly suited to the concept of atom when it was developed by chemists in the early nineteenth century, ie as the smallest part of a pure body.
So the atom of aluminum will remain unchanged, whatever the reaction it will undergo, it is only its molecular form that will change.
Investigate The Kinetics Of The Amazing Iodine Clock Reaction
Molar mass P2O5 = 31 x 2 + 16 x 5 => 142 g/mol
142 g ---------------- 6.02 x 10²³ molecules
0.920g g ------------ ( molecules )
molecules = 0.920 x ( 6.02 x 10²³ ) / 142
molecules = 5.53 x 10²³ / 142
= 3.89 x 10²¹ molecules
1 molecule P2O5 -------------------------- 7 atoms
3.89 x 10²¹ molecules -------------------- ( atoms )
atoms = ( 3.89 x 10²¹) x 7 / 1
atoms = 2.72 x 10²² atoms of P2O5
hope this helps!
