In the periodic table, the elements that are adjacent to the "stair step" are called actinide series nonmetals metalloids alkali metals

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Metalloids

Explanation:-

The stair step line is a line in the periodic table that divides the metals on one side and the non metals on the other side. So the elements which lie on the stair step line must have properties in between those exhibited by the metals and those by the non metals.

Such elements we know are called metalloids. Thus In the periodic table, the elements that are adjacent to the "stair step" are called metalloids.

explanation:

metals have excess of electrons whereas non-metals have deficiency of electrons. thus, in order to gain stability metals easily donate their electrons to the non-metals.

for example, electronic configuration of sodium is and electronic configuration of phosphorous is .

when a phosphorous atom and sodium atom combine together then sodium will donate is extra one electron to the phosphorous atom. as a result there will be formation of ionic bond between sodium and phosphorous.

the reaction will be as follows.

there, are three sodium sodium atoms and each of them will donate its one extra electron to phosphorous atom. thus, the sub-shell of phosphorous gets completely filled.  

thus, we can conclude that electrons are transferred from atoms of sodium to atoms of phosphorous. this transfer makes the sodium atoms donate one electron and the phosphorous atoms to gain one electron. as a result, the sodium and phosphorus atoms strongly attract each other.

the dependant variable is spilled water

the independent is the heat