How much of a 500g sample of potassium-42 is left after 37.2 hours if the half-life of potassium-42 is 12.4 hours.

The diagram shows the positions of the sun, moon and earth during spring tides, when the high tides are at their highest and low tides at their lowest. what is it about these positions that causes these high and low tides?

Which of the following shapes would represent a molecule with two bonded atoms and 3 lone pairs on only one of them , trigonal planar , bent , trigonal pyramidal , linear

What is the atomic number of an atom that has 6 protons