Average atomic mass is the weighted average atomic masses with regard to the relative abundance of the isotopes
average atomic mass of Li = relative abundance of Li-6 x mass of Li-6 + relative abundance of Li-7 x mass of Li-7
average atomic mass of Li = (7.42% x 6.0151 a.m.u) + (92.58% x 7.0160 a.m.u)
= 0.446 + 6.495
= 6.941 amu
average atomic mass of Li is 6.941 amu
solution:
You need to find the frequency, and they have already given you the wavelength. And since you already know the speed of light, you can use formula (2) to answer this problem. Remember to convert the nano meters to meters because the speed of light is in meters. 

An electrolyte<span> is a substance that produces an electrically conducting solution when dissolved in a polar solvent, such as water. </span>
Explanation:
i think right one is c.
it is because proton is different in each element.
Hey there!
The Buoyant force is going to be equal to the weight of the water displaced and it would be like this 100 L(9.8 N/L) = 980 N.
Hope this helped and mind marking me brainliest. Thank you!