On your graph, the data points between the red squares are data for elements with atomic numbers 3 through 9. Locate these elements on your periodic table. What term or description would you use to identify these elements with respect to the periodic table? They are all alkali earth metals (family 2) on the periodic table.

They are all in period 2 on the periodic table

They are all nonmetals on the periodic table.

They are all in period 4 on the periodic table

Numbers three to nine are: Lithium, Beryllium, Boron, Carbon, Nitrogen, Oxygen and Fluorine. They are all in period 2 on the periodic table.

so here we go

atomic mass

239 + 1 = y + 134 + 3 combine like terms

240 = y + 137             subtract 137 from both terms

240 - 137 = y

103 = y

atomic number

94 = z +54 + 0

94 = z + 54               subtract 54 from both sides.

40 = z

answer

chemical changes occur when a substance combines with another to form a new substance, called chemical synthesis or, alternatively, chemical decomposition into two or more different substances. these processes are called chemical reactions and, in general, are not reversible except by further chemical reactions. some reactions produce heat and are called exothermic reactions and others may require heat to enable the reaction to occur, which are called endothermic reactions. understanding chemical changes is a major part of the science of chemistry.