A student carried out a reaction between calcium carbonate solid (CaCO3) and hydrochloric acid (HCl) producing dissolved calcium chloride (CaCl2) carbon dioxide and water. Write the balanced symbol equation for this reaction, including state symbols.

Idon't understand what to put on the left lines i'm confused can anyone ?

This is a characteristic of the elements in the periodic table that shows a pattern. it may increase or decrease across or down the table.

The atomic radius of sodium is 186 pm and of chlorine is 100 pm. the ionic radius for na+ is 102 pm and for cl– is 181 pm. in going from na to cl in period 3, why does the atomic radius decrease while the ionic radius increases? a. the inner electrons in the sodium cation shield its valence electrons more effectively than the inner electrons in the chloride anion do. b. the inner electrons shield the valence electrons more effectively in the chlorine atom than in the chloride anion. c. the outermost electrons in chloride experience a smaller effective nuclear charge than those in the sodium cation do. d. the outermost electrons in chloride experience a larger effective nuclear charge than those in the sodium cation do. e. monatomic ions are bigger than the atoms from which they are formed.