<span>Barium - A) Great conductor of heat and electricity
Potassium - B) Malleable and highly reactive
Boron - C) Has properties of both metals and nonmetals
Neon - D) Nonreactive gas
Let's look at each element and it's place on the periodic chart to see what matches.
Potassium - This is on the far left column for alkali metals. This means it's highly reactive and since it's a metal, it's both malleable and conductive. Looking at the available options, "B) Malleable and highly reactive" is the best choice.
Barium - This element is in the second column from the left, so it's a fairly reactive metal, but not nearly as reactive as Potassium above. So "A) Great conductor of heat and electricity" is the best choice here, although I wouldn't call it "great". The resistivity of barium is about 20 times larger than copper.
Boron - This element is about in the middle of the periodic chart, so it does have the properties of both metals and nonmetals. So "C) Has properties of both metals and nonmetals" is the best choice.
Neon - This is in the far right column for noble gasses. Very non-reactive. So "D) Nonreactive gas" is the best choice.</span>
Answer:
Explanation:
Oppositely charged particles attract each other, while like particles repel one another. Electrons are kept in the orbit around the nucleus by the electromagnetic force, because the nucleus in the center of the atom is positively charged and attracts the negatively charged electrons.
