In which of the following elements is the valence electron farthest from the nucleus? #3 lithium
#11 sodium
#19 potassium
#37 rubidium

Zoe is investigating the composition of substance a, an unknown substance. using chemical processes, she analyzes substance a and determines it is composed of sodium, oxygen, and hydrogen atoms in a ratio of 1 : 1 : 1. what is substance a? a. a compound b. an element c. a heterogeneous mixture d. a homogeneous mixture

Astudent is asked to identify and element that is pale yellow brittle solid and does not conduct electricity. at which location in this periodic table would the element most likely be found?

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