3. choose the best answer. found in air and water, ____ is the earths most abundant element. iron carbon…

3. choose the best answer. found in air and water, ____ is the earths most abundant element. iron carbon oxygen chlorine 4. choose the best answer. metalloids have the properties of ____ and are elements in the center of the periodic table. noble gases metals only lanthanide elements both metals and nonmetals

3. choose the best answer. found in air and water, ____ is the earths most abundant element. iron carbon oxygen chlorine 4. choose the best answer. metalloids have the properties of ____ and are elements in the center of the periodic table. noble gases metals only lanthanide elements both metals and nonmetals

Answer

Brief Explanations:

  • For the first question, oxygen is abundant in air (about 21% by volume) and is a key component of water ($H_2O$). Other elements like iron, carbon and chlorine are not as abundant as oxygen on Earth.
  • For the second question, metalloids have properties intermediate between metals and non - metals. They are located along the staircase - like line on the periodic table, not in the center where transition metals are located, and they do not have properties of noble gases or lanthanide elements.

Answer:

  1. C. oxygen
  2. E. both metals and nonmetals