Lithium is an element that has an electronic configuration of 2,1. So when forming bonds, it tries to release one of its electrons in the last shell to reach the octet state. Normally when atoms release electrons they get positive charge since the number of protons which bear positive charge, is higher than number of electrons which bear negative charge. So when reaching its octet state, lithium gains positive charge!
Hope this helps! Tbh am not good at explaining. If u have any doubts, ask me!
        
             
        
        
        
Answer:
148 grams of relative atomic mass
Explanation:
magnesium atomic mass : 24
nitrogen : 14
oxygen : 16
24 × 1
14 × 1 × 2
16 × 3 × 2
24 + 28 + 80 = 148 grams
 
        
             
        
        
        
B) A chemical change because the nail reacts with water/oxygen to create rust (a type of oxide)
        
             
        
        
        
Answer:
True
Explanation:
Well,I hope it helps....
Just correct me if I'm wrong..
 
        
             
        
        
        
Answer:
Option B
Explanation:
Salt is a non-volatile solute and hence adding salt will increase the boiling point of water and hence reduce the vapor pressure. While on the other hand, adding more water will require more time to boil and hence produce vapor and thus the vapor pressure. Shaking will also not help in increasing the vapor pressure. Thus, only increasing the temperature of the water will create more vapors at a faster rate and hence increase the vapor pressure. 
Thus, option B is the correct answer