What's 213bi after undergoing alpha decay

Which of the following elements is a representative element? a. chromium (cr) b. aluminum (al) c. mercury (hg) d. silver (ag)

Which metal exist in liquid state and can be cut with knife ?

Great amounts of electromagnetic energy from our sun and other bodies in space travel through space. which is a logical conclusion about these electromagnetic waves? their energy must be very their frequency must be very low these waves can travel without a medium they only travel through a vacuum of space