Respuesta :

atomic number 3 atomic number 4

symbols Li symbol Be

atomic weight :6.9 atomic weight:9

proton of Li is 3

neutron is 3.9

electro negativity is ,it hasn't discharged so it is electro negativity =3-0= 3

another onebis calculate by this formula

3
LI
Lithium
6.941
P= 3 N= 3 E= 3

4
BE
beryllium
9.012
P= 4 N= 5 E= 4

Hope this helps:D