Please help 30 POINTS the symbol, the group number, and the period of each of the following elements: nitrogen, sodium, iodine, and mercury
and if you can do the rest that would be great

What is the momentum of a 2 kg object moving at 15 meters per second

Photoelectrons with a maximum speed of 6.50 x 107 m/s are ejected from a surface in the presence of light with a frequency of 6.75 x 1014hz. if the mass of an electron is 9.10 x 10-31 kg, calculate in joules the maximum kinetic energy of a single electron. 3.84 x 10-15 j 1.92 x 10-15 j 5.92 x 10-23 j 3.07 x 10-16 j

Explain what it means to view something from a frame of reference. provide an example that illustrates your explanation. (4 points)