CHAPTER 2 BIO TEST

A compound contains two or more different _______ in a fixed ratio

The four most common elements in a living organisms are hydrogen, _______, oxygen, and nitrogen

The almost identical masses of protons and neutrons are measured in ______

(or atomic mass unit/AMU)

typically, nitrogen atoms are composed of electrons, protons, and neutrons. An isotope of nitrogen

could have more _______ than the usual nitrogen atom

The sodium atom contains 11 electrons, 11 protons, and 12 neutrons. What is the mass number of sodium?

the properties of an atom change when the ______ electrons ( electrons

in the outer shell) are altered

________ is a trace element commonly added to table salt

an atom of boron has an atomic number of 5 and an atomic mass of 11. Therefore, boron has __ electrons

a __________ isotope is one that decays

In a __________ bond, the partners share a pair of electrons