How do elements change from left to right across a period of the periodic table?

Balance this equation co2(g) + h2o (g) show that the balanced equation obeys the law if conversation of mass

How do you identify the anode on a power source such as a battery? how do you identify the cathode? how are terms anion and cation?

What is a possible quantum number set for an electron in the 3s orbital of a magnesium atom