The Chemistry of Life Organic Compounds Exam Questions with Correct Answers

an element is a substance that cannot be separated into simpler parts by - Answer-chemical reactions over 96% of an organism's weight is made up of the four elements - Answer-oxygen, hydrogen, carbon, nitrogen the three main parts of an atom are the _________. The ____________, compose the atomic nucleus, and the ___________ occupy the mostly empty space surrounding the nucleus. - Answer-neutrons, protons, electrons a ______ have one unit of positive charge, _______ are netural, and __________ have a negative charge - Answer-proton, neutron, electrons the number of protons in an atom is called the - Answer-atomic number the symbol 8 O 6 indicates taht oxygen has ______ protons - Answer-8 an atom is uniquely identified by its.... - Answer-number of protons protons plus neutrons determine... - Answer-atomic mass the total number of protons and neutrons in an atom is referred to as the - Answer-mass number an atomic mass unit (amu) is also called a - Answer-dalton the _________ of isostopes vary, but the __________ remains constant - Answer-neutrons, protons unstable isotopes that emit radiation when they decay are termed - Answer-radioisotopes electrons with the same energy comprise an ______ - Answer-electron shell the electrons in the outermost energy level of an atom are called ________ electrons - Answer-valence a chemical compound consists of - Answer-atoms of two or more different elements that are combined in a fixed ratio