Human Biology Chapter 2 Flashcards
An atom has an equal number of ____ and _____and is electrically ______
electrons; protons; neutral
What has a negative charge?
electron
The atomic number of an element is its number of _____
protons
The atomic mass of an element is its number of ____
protons and neutrons
Isotopes of an element differ from each other by their number of
neutrons
An atom has an atomic number of 11 and an atomic mass of 23. How many neutrons in its nucleus?
12 neutrons
In an atom the number electrons = the number of ____
protons
A chlorine atom with an atomic mass of 35 and am atomic number of 17 possesses ____ protons and ____ neutrons
17; 18
Chlorine has 7 electrons in its outermost energy level. To become stable must it lose or gain electrons? How many?
Gain 1
Which atom has the greatest atomic mass:
- carbon
- hydrogen
- oxygen
- nitrogen
oxygen
An ion is an atom that has ____
gained or lost electrons
An atom that has lost one electron is a positive or negative ion?
positive ion
a bond formed as a result of sharing of electrons is called a ____ bond
covalent
Nitrogen has 5 electrons in its outermost energy shell. How many electrons can it share with outer atoms to become stable?
3
Weak bonds that form between polar covalent molecules, such as water, are called ____ bonds
hydrogen
a pH of 7.4 possesses more ____ than ____
OH- than H+
A pH f 2 is _____ as a pH of 5
1000 times as acidic
A chemical that prevents large changes in pH is best called a
buffer
Which of the following is an inorganic molecule:
- protein
- lipid
- water
- carbohydrate
water
Anything that has mass and occupies space is called
matter
The purest substance that contains only one type of atom is called a(n)
element
What are found in the nucleus of an atom and has a positive charge?
proton
____ from isotopes helps to stabilize their nuclei
radiation
atoms contain 3 subatomic particles:
protons; neutrons; electrons
the atomic number is equal to the number of
protons
atoms of an element that differ by their number of neutrons are called
isotopes
an atom that gains or loses an electron or electrons is called a(n)
ion
unequal sharing of electrons
polar covalent bond
a bond that forms between the charged ends of two water molecules
hydrogen bond
the branch of chemistry that deals with carbon compounds is called
organic chemistry
new species can arise through a process called
evolution
in the scientific method a ____ is a tentative explanation of a phenomeon
hypothesis
what is the purest form of matter that cannot be separated into different substances by chemical means?
element
what is a negatively charged particle that is found in the nucleus of an atom?
neutron
what is a positively charged particle that is found in the nucleus of an atom?
proton
Humans are unique among animals because of their
complex culture
in an experiment, the control group
does not receive experimental treatment
evolution is something that occurs in ____
populations
ions can have a ____ or a _____ charge
positive or negative
a molecule that helps to regulate pH is called
buffer
pH measures ____
the level of acidity
