What are the groups in Mendeleev's table?

What will a positive and a negative charge do if they are separated from each other?

The softest and hardest minerals are: softest hardest

Select for each of the following statements whether it is correct or incorrect. (a) in an isothermal expansion of an ideal gas. (b) the temperature remains constant. (b) the pressure remains constant. (c) there is work done by the gas. (d) there is heat added to the gas. (e) the change in internal energy equals zero.