BIOL 1201: Exam 1 Questions With 100%
Correct Answers
A substance that cannot be broken down into other substances by ordinary chemical procedures is
a(n) _____.
element
Organisms are largely composed of __ elements.
11
About 25 of the 92 natural elements are known to be essential to life. Which four of these 25
elements make up approximately 96% of living matter?
carbon, hydrogen, nitrogen, and oxygen
What determines solubility?
"like dissolves like"
Atom
Smallest unit of matter that retains all the properties of that element
What is the mass and charge of protons?
Mass: 1 Dalton
Charge: +1
What is the mass and charge of neutrons?
Mass: 1 Dalton
No charge
What is the mass and charge of electrons?
Mass: close to none (about 1/10000 that of a proton or neutron)
Charge: -1
Which subatomic particle(s) always have a positive charge?
protons
Atomic Number
equal to the number of protons in an atoms
In a neutral atom, the atomic number is equal to...
the number of protons
What is the atomic number of an atom that has 6 protons, 6 neutrons, and 6 electrons?
6
.From its atomic number of 15, it is possible to predict that phosphorus always has ___.
,15 protons
Atomic Mass
the sum of the number of protons and neutrons in an atom
Fluorine's atomic number is 9 and its atomic mass is 19. How many neutrons does fluorine have?
10 neutrons
.An uncharged atom of boron has an atomic number of 5 and an atomic mass of 11. How many
protons does boron have?
5 protons
.Changing the number of _____ would change an atom into an atom of a different element.
protons
Isotopes
variants of an atom that have different atomic masses due to differing numbers of neutrons
What refers to atoms with the same atomic number but different atomic masses?
isotopes
True or False: An atom with more neutrons than the atom described in the question above will have a
different valence.
False
Where are protons located within an atom?
the nucleus
Where are neutrons located within an atom?
the nucleus
Where are electrons located within an atom?
orbitals, or shells, around the nucleus of an atom
What are the names of the first three electron orbitals and how many electrons do each of them
contain?
K-shell: 2 electrons
L-shell: 8 electrons
M-shell: 8 electrons
An atom with the atomic number 9 will have _______ electrons in its outermost electron shell.
7
Electrons always try to be in the ____ orbital or energy shell.
, lowest
Valence
the number of electrons that either need to be gained or lost to fill the outermost shell with electrons
What is significant about valence?
Valence predicts the number of bonds that atoms will form
An atom with the atomic number 15 has a valence of __.
3
Valence Electrons
electrons in the outermost shell of an atom
What is the difference between valence and valence electrons?
Valence is the NUMBER of electrons that either need to be gained or lost to fill the outermost shell
with electrons, while valence electrons are the ELECTRONS in the outermost shell of an atom
When are atoms the most stable and nonreactive?
Atoms are stable and nonreactive when their outer electron shells are full.
Why do atoms attempt to either gain or lose electrons?
Atoms attempt to either lose or gain electrons in order to fill their outer shells and become stable
Chemical bonds are the result of ____________.
electrical attractions between atoms that either gain, lose, or share electrons
Ionic Bonds
bonds that are the result of very strong electrical attractions, where electrons are either lost or gained
An ionic bond involves _____.
an attraction between ions of opposite charge
Ionic bonds are strongest when _____.
they are dry
Atoms with the same number of protons but with different electrical charges _____.
are different ions
.In salt, what is the nature of the bond between sodium and chlorine?
ionic
Covalent Bonds
Correct Answers
A substance that cannot be broken down into other substances by ordinary chemical procedures is
a(n) _____.
element
Organisms are largely composed of __ elements.
11
About 25 of the 92 natural elements are known to be essential to life. Which four of these 25
elements make up approximately 96% of living matter?
carbon, hydrogen, nitrogen, and oxygen
What determines solubility?
"like dissolves like"
Atom
Smallest unit of matter that retains all the properties of that element
What is the mass and charge of protons?
Mass: 1 Dalton
Charge: +1
What is the mass and charge of neutrons?
Mass: 1 Dalton
No charge
What is the mass and charge of electrons?
Mass: close to none (about 1/10000 that of a proton or neutron)
Charge: -1
Which subatomic particle(s) always have a positive charge?
protons
Atomic Number
equal to the number of protons in an atoms
In a neutral atom, the atomic number is equal to...
the number of protons
What is the atomic number of an atom that has 6 protons, 6 neutrons, and 6 electrons?
6
.From its atomic number of 15, it is possible to predict that phosphorus always has ___.
,15 protons
Atomic Mass
the sum of the number of protons and neutrons in an atom
Fluorine's atomic number is 9 and its atomic mass is 19. How many neutrons does fluorine have?
10 neutrons
.An uncharged atom of boron has an atomic number of 5 and an atomic mass of 11. How many
protons does boron have?
5 protons
.Changing the number of _____ would change an atom into an atom of a different element.
protons
Isotopes
variants of an atom that have different atomic masses due to differing numbers of neutrons
What refers to atoms with the same atomic number but different atomic masses?
isotopes
True or False: An atom with more neutrons than the atom described in the question above will have a
different valence.
False
Where are protons located within an atom?
the nucleus
Where are neutrons located within an atom?
the nucleus
Where are electrons located within an atom?
orbitals, or shells, around the nucleus of an atom
What are the names of the first three electron orbitals and how many electrons do each of them
contain?
K-shell: 2 electrons
L-shell: 8 electrons
M-shell: 8 electrons
An atom with the atomic number 9 will have _______ electrons in its outermost electron shell.
7
Electrons always try to be in the ____ orbital or energy shell.
, lowest
Valence
the number of electrons that either need to be gained or lost to fill the outermost shell with electrons
What is significant about valence?
Valence predicts the number of bonds that atoms will form
An atom with the atomic number 15 has a valence of __.
3
Valence Electrons
electrons in the outermost shell of an atom
What is the difference between valence and valence electrons?
Valence is the NUMBER of electrons that either need to be gained or lost to fill the outermost shell
with electrons, while valence electrons are the ELECTRONS in the outermost shell of an atom
When are atoms the most stable and nonreactive?
Atoms are stable and nonreactive when their outer electron shells are full.
Why do atoms attempt to either gain or lose electrons?
Atoms attempt to either lose or gain electrons in order to fill their outer shells and become stable
Chemical bonds are the result of ____________.
electrical attractions between atoms that either gain, lose, or share electrons
Ionic Bonds
bonds that are the result of very strong electrical attractions, where electrons are either lost or gained
An ionic bond involves _____.
an attraction between ions of opposite charge
Ionic bonds are strongest when _____.
they are dry
Atoms with the same number of protons but with different electrical charges _____.
are different ions
.In salt, what is the nature of the bond between sodium and chlorine?
ionic
Covalent Bonds
