Science
false
Sodium and chlorine atoms combine readily because they both tend to lose electrons.
compound
A chemical substance composed of atoms of two or more elements chemically bonded to one another
true
A salt is produced when an acid reacts with a base.
neutral
A solution that contains equal numbers of hydrogen and hydroxide ions would be called what?
true
An atom that has gained or lost electrons is called an ion.
H
An example of a symbol for an element is what?
protons and neutrons
Atomic mass is determined by what?
protons and electrons
Atoms are electrically neutral because they have the same number of what?
ionic, covalent, and hydrogen
Atoms form compounds that are held together by bonding. What Three types can be formed?
charges
Atoms of different elements may have identical what?
ionic
Atoms of opposite charge can combine to form a/an what bond?
element
Containing only one type of atom
carbon, hydrogen, oxygen, and nitrogen
Four elements which comprise over 95% of the human body are what?
a molecule contains two hydrogen atoms and one oxygen atom
H2O means what?
three
How many hydrogen atoms in a molecule of NH3 are there?
negative
If an atom is gained, the atom has a what charge?
positive
If an atom is lost, the atom has a what charge?
ion
If an atom loses or gains an electron, it is called what?
does not
It the outer shell of the atom is full, if ___ react readily with other atoms.
false
Of the known elements only about ten are needed by living things.
elements
Table salt is a compound composed of two what, sodium and chlorine.
16
The atomic mass of an element whose atoms consist of eight protons, eight neutrons, and eight electrons is what?
nucleus
The mass of an atom is contained primarily in what?
water
The most important compound in biological systems that has the formula H2O is what?
atomic number
The number of protons determines what?
false
The number of protons within an atom of an element is equal to its atomic mass.
orbital
The path surrounding the nucleus of an atom in which electrons are normally located.
carbon, hydrogen, oxygen, and nitrogen
The principal elements in living things are what?
outer
The reactivity of an atom is due to its number and arrangement of electrons in what energy level or orbit.
true
The symbol Na+ represents a sodium atom that has lost an electron.
protons, neutrons, electrons
The three subatomic particles are what?
true
Water is an example of a compound.
electrons
carries negative electrical charges
neutron
carries no electrical charge
protons
carries positive electrical charges
false
A substance that releases hydrogen ions in water is a base.
molecule
A unit of matter composed of two or more atoms held together by chemical bonds.
mixture
Two of more substances mixed together but not chemically combined.
covalent bond
When two atoms combine by sharing of a pair of electrons, it is what kind of bond?