What is the significance of the atomic number, Z, above each atomic symbol in the periodic table?

The reaction of two positively charged objects that are near each other

The cathode-ray tube was essential to the work of:

A radioactive element undergoes decay via the loss of two alpha particles to form a stable daughter isotope. Following the decay, what would the atomic number of this newly created stable isotope be?

Calculate the efficiency of a fossil-fuel power plant that consumes 380 metric tons of coal each hour to produce useful work at the rate of 720 MW. The heat of combustion of coal (the heat due to burning it) is 28 MJ/kg.

Why is a blizzard whiteout dangerous?

A Car is lifted a certain distance in a service station and therefore has potential energy relative to the floor. if it was lifted twice as high, how much potential energy would it have?

How long does it take a 750-w coffeepot to bring to a boil 0.75 l of water initially at 11°c? assume that the part of the pot which is heated with the water is made of 280 g of aluminum, and that no water boils away?

An electric motor rotating a workshop grinding wheel at a rate of 151 rev/min is switched off. Assume constant angular deceleration of magnitude 2.23 rad/s 2. Through how many revolutions does the wheel turn before it finally comes to rest

1. What is the atomic number of an atom? Why is this number important? |

The car travels down the road at 60mph for 1.5 hours. How far does it go?