Human Biology Chapter 2 Flashcards
(41 cards)
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
