An atom's Lewis dot structure has four dots. Which of the following elements could it be, and why? O Aluminum, because it is a metal with four electrons in period 3.
O Beryllium, because it is in period 2 and has four total electrons.
O Carbon, because it is in group 14 and has four valence electrons.
O Calcium, because it is an alkaline earth metal in period 4.​

Determine the empirical formula for succinic acid that is composed of 40.60% carbon, 5.18% hydrogen, and 54.22% oxygen.

The appropriate concentration for an iodine sanitizer is

High-pressure liquid chromatography (hplc) is a method used in chemistry and biochemistry to purify chemical substances. the pressures used in this procedure range from around 500 kilopascals (500,000 pa) to about 60,000 kpa (60,000,000 pa). it is often convenient to know the pressure in torr. if an hplc procedure is running at a pressure of 1.03×108 pa , what is its running pressure in torr?