Chapter 2: The Chemical Basis of Life Flashcards
What is ocean acidification?
a process by which greenhouse gases admitted to the atmosphere are getting into the ocean and changing the ocean’s composition
What are all living organisms made of?
Cells!
What are cells composed of?
Molecules
What are molecules composed of?
atoms
What are molecules?
made up of multiple atoms
What are atoms?
the smallest basic structure of elements
What is an element?
made of one type of atom, but can contain multiple of that atom
What is the periodic table of elements?
depicts the different substances that exist in nature or that have been synthesized in labs or nuclear reactors’
What elements are 96% of living matter composed of?
Hydrogen (H), Carbon ©, nitrogen (N), and oxygen (O)
Where are protons, neutrons, and electrons located in an atom?
The nucleus contains protons and neutrons, with electrons ‘orbiting’ the outside
protons
positive charge
Neutrons
neutral charge
Electrons
negative charge
What is the atomic number?
the number of protons an atom has
What is the mass number?
the number of protons + neutrons
What is the atomic mass?
approximately equal to its mass number (takes electrons into account)
What are isotopes?
the same number of protons but different numbers of neutronsForms of an element with different numbers of neutrons
What does most an atom’s volume consist of?
empty space
How are electrons organized?
located in different electron shells/orbitals, each with a characteristic distance from the nucleus
How are chemical bonds formed?
An atom whose outer electron shell is not full tends to interact with other atoms and share, gain, or lose electrons, resulting in attractions
How many electrons are needed for a full outer shell?
8
How is an atom electrically neutral?
When the number of protons and the number of electrons in an atom are the same, the charges balance
What is atomic weight?
an average of all the masses of the naturally occurring isotopes based on their abundance in nature
How many electrons can each orbital hold?
2 (a pair)
What is an atom’s valence shell?
The outermost electron shell of an atom
What are valence electrons?
an electron in the outermost electron shell; these electrons tend to be involved in chemical bonding
What is an atom’s valence?
The number of unpaired electrons found in an atom’s valence shell
