Biochemistry unit test section 1
what do all atoms of the same element have in common?
# of protons
neutrons
# varies slightly among atoms of the same element
mass of protons and neutrons
1 amu (atomic mass unit)
What is H20 made up of?
2 atoms of hydrogen and 1 atom of oxygen
how many electrons can the first energy level hold?
2 electrons
how many atoms are in C6H1206?
24 atoms
how many atoms are in BO2?
3 atoms
how many atoms are in NH3?
4 atoms
the atomic number is 6, how many protons are there?
6
how many electrons can levels 2-7 hold?
8 electrons( octet rule)
Neutron formula
N=AM-AN (atomic mass-atomic #)
volume
The amount of space an object occupie
compound
a pure substance made up of atoms of two or more elements
how do you find the atomic mass of an atom?
add the # of protons and neutrons in an atom
ion
an atom or molecule w/ a net electric charge due to the loss or gain of 1 or more electrons
matter
anything that has mass and volume (everything in the universe is composed of it)
negative ions
atoms that gain electrons
positive ions
atoms that lose electrons
Coefficient
before a formula; tells the # of molecules
What happens in a chemical reaction?
bonds are broken, atoms are rearranged, and new chemical bonds are formed
How are elements arranged on the periodic table?
by atomic number
nucleus
central core of an atom(positively charged)
how are isotopes of the same element produced?
different # of neutrons
unique chemical symbol
each element has one; consists of 1-2 letter and first letter is always capitalized
nonpolar covalent bond
equal sharing of electrons "double bond" (ex: 02)
covalent bond
formed when two atoms share one or more pairs of electrons
electron cloud
general area where electrons are located
why do atoms tend to react/combine with other atoms?
in order to become more stable
How many elements are there?
more than 100(92 naturally occurring)
electrons
negatively charged high energy particles with little or no mass
where are protons and neutrons found?
nucleus of an atom
do outer or inner levels of the nucleus have more energy?
outer energy levels
valence electrons
outermost number of electrons
what is 90% of the mass of an organism?
oxygen, carbon, hydrogen, nitrogen
What does the nucleus contain?
positively charged protons and neutral neutrons(also contains most of an atoms mass)
Element
pure substance that can't be broken down chemically into simpler kinds of matter
mass
quantity of matter an object has
chemical formula
shows the kind and proportion of atoms of each element that occurs in a particular compound
element that is likely to form ionic bonds
sodium
Subscrpit
tells the # of molecules of each element (after a symbol)
ionic bonds
the complete transfer of valence electron(s) between atoms. It is a type of chemical bond that generates two oppositely charged ions.(some atoms become stable by losing or gaining electrons)
atomic mass
the number of protons and neutrons added together
atomic number
the number of protons in the nucleus of an atom
what happens if the # of protons are balanced by an equal # of negatively charged electrons?
the overall charge is neutral
molecules
the smallest part of a compound that have all the properties of the compound
atoms
the smallest part of an element that retains all the properties of that element
polar covalent bond
unequal sharing of electrons (ex: H20)
how many energy levels can atoms have?
up to 7 energy levels (1 is closet to nucleus and 7 is farthest)
Example of a compound
water
When are atoms most stable?
when their outermost energy level l is full