what is the mass number of the isotope lithium-7?

7

Explanation:

isotopes are named after there mass number. because there mass number is different and protons no is same

a high pressure system is a dense air mass that is usually cooler and drier than the surrounding air. a low pressure system is a less dense air mass that is usually wetter and warmer than the surrounding air.

in general, areas that experience high atmospheric pressure also experience fair weather. low pressure systems can cause the formation of clouds and storms. air usually flows from areas of high pressure to areas of low pressure..

power out to power in less than 100%