Answer: Be= 2, C =4, Li = 1 and B=3
Explanation:
The valence shell can be define as the outermost shell of an atom that contains the valence electrons.
Beryllium (Be), electronic configuration; 1s2 2s2, = 2 electrons in its valence shell.
Carbon (C), electronic configuration; 1s2 2s2 2p2, = 4 electrons in its valence shell.
Lithium (Li), electronic configuration; 1s2 2s1 = 1 electron in its valence shell.
Boron (B) , electronic configuration; 1s2 2s2 2p1 = 3 electron in its valence shell.
Answer:
2,7 m
Explanation:
You can solve this doing an energy balance:
![m*g*h-\frac{1}{2} *m*v^{2} =41,7[J]](https://tex.z-dn.net/?f=m%2Ag%2Ah-%5Cfrac%7B1%7D%7B2%7D%20%2Am%2Av%5E%7B2%7D%20%3D41%2C7%5BJ%5D)
Solving this equation to get h:

Replacing the values and solving brings to 2,7 m