What period and group (number and name) is Selenium in?

An animal cell loses the ability to convert energy stored in food to energy that the cell can use. which of the cell's organelles has stopped working? a. the mitochondria b. the nucleus c. the vacuoles d. the endoplasmic reticulum

Question 3(multiple choice worth 4 points) (04.04 lc) what does it mean when an element is reduced? it empties a valance shell, reducing its atomic radius. it gains electrons, reducing its overall charge. it increases electronegativity, reducing its ability to bond. it loses electrons, reducing its electron number.

How many grams are in 68.2 molecules of br2?