1. In the notation, 1s2, the number 1 represents the where electrons are located.
energy level
outer shell
2.
The four parts, or blocks, on the periodic table are , , d, and f.
s, p
a, b
3.
The 2 in 1s2 represents the number of located in that energy level.
electrons
protons

The experiments with static charges were done by:

Which of the following represents an upside-down image?

Acylinder with a movable piston contains 11.7 moles of a monatomic ideal gas at a pressure of 1.32×10^5 pa. the gas is initially at a temperature of 300 k. an electric heater adds 43200 j of energy into the gas while the piston moves in such a way that the pressure remains constant. cp=20.79 j k^−1 mol^−1 for a monatomic ideal gas, and that the number of gas molecules is equal to avogadro's number (6.022×10^23) times the number of moles of the gas. (a) what is the temperature of the gas after the energy is added? (b) what is the change in volume of the gas? (c) how much work is done by the gas during this process?