Chapter 1 & 2 Flashcards
What are the 7 characteristics of all living things?
- organization and cells
- responds to stimuli
- homeostasis
- metabolism
- growth, development and cell specialization
- reproduction
- change through time
What is homeostasis?
the maintenance of stable internal conditions even when conditions change (temperature, water content, blood glucose level, nutrients, etc).
What are the three domains of all living things?
bacteria, archaea, and eukarya
What are the six kingdoms that the three domains are divided into?
archaea, bacteria, protista, fungi, plantae, and animalia
What is an atom?
a substance that cannot be broken down into any other substance and continue to have the same properties
How many elements are are important to living things?
<30%
What are the four elements 90% of living organisms composed of?
oxygen, carbon, hydrogen, and nitrogen
What are the three parts of the atom (subatomic particles)?
proton, neutron, electron
What is the charge of a proton and where is it found?
+, nucleus of atom
What is the charge of a neutron and where is it found?
there is no charge, nucleus of atom
What is the charge of an electron and where is it found?
-, high energy particles that are in constant motion moving in an electron cloud around the nucelous
What does the number of protons tell about an element?
it’s atomic number
Can the number of neutrons vary from one atom of an element to another?
yes
What are the electron’s distance from the nucleus based on?
energy levels called orbitals
What energy levels do electrons fill first?
the lowest level
What determines the chemical characteristics of an element?
the number and location of the electrons
What are isotopes?
atoms of the same element with different numbers of neutrons
What is a chemical compound?
a substance formed by the chemical combination of 2 or more elements
What do chemical formulas tell?
which elements are present in a compound and their ratio
What are valence electrons?
electrons farthest away from the nucleus that are involved in forming chemical bonds
When do chemical bonds form between two atoms?
when valence electrons move between them either by being transferred or shared between atoms
When are covalent bonds formed?
when valence electrons are SHARED between atoms (ex: sodium chloride or salt)
How many electrons can atoms share?
1-3
When are ionic bonds formed?
when 1 or more valence electrons are TRANSFERRED from one atoms to another