Science Ch. 13
What is formed when atoms share one or more pairs of electrons?
covalent bond
When ions bond, they form a repeating three-dimensional patterned called a(n)
crystal lattice
What property gives metals the ability to be drawn into thin wires?
ductility
A model that shows only the valence electrons in an atom is a(n)
electron dot diagram
Covalent compounds are formed when a group of atoms share...
electrons
When electrons pull away from atoms, ______ is needed.
energy
family on the periodic table to which an element belongs
group
Which group on the periodic table contains elements that do not normally form chemical bonds?
group 18
A chemical bond that forms when electrons are transferred from one atom to another is a
iconic bond
If a sodium atom loses its only valence electron to another atom, the sodium atom because a sodium ______.
ion
In a crystal lattice each ion is bonded to the
ions around it
What property means that the metal can be hammered into sheets?
malleability
A bond formed by the attraction between positively-charged metal ions and the electrons in the metal is a(n)
metallic bond
The group of atoms that make up a covalent compound is called a(n)
molecule
What is the smallest particle in which covalent bonds can be divided?
molecule
What usually consists of two or more atoms joined in a definite ratio?
molecule
Some atoms gain electrons during chemical changes and have a...
negative charge
When a metal meets a nonmetal, the nonmetal atom becomes
negatively charged
What determines whether an atom will form bonds?
number of valence electrons
An ionic bond is an attraction between
oppositely charged ions
When a metal meets a nonmetal, electrons are transferred and the metal atoms become
positively charged
When atoms lose electrons through an ionic bond, they become...
positively charged
What substance results from combining atoms of carbon, hydrogen, and oxygen?
sugar
Where does the energy needed to take electrons from metals come from?
the formation of negative ions
an explanation of a phenomenon that is based on observation, experimentation, and reasoning
theory
Most metals have few _______ _________ and form positive ions
valence electrons
What are the electrons found in the outermost energy levels of an atom called?
valence electrons
What do elements within a group number have the same number of?
valence electrons
an electron in the outermost energy level
valence electrons
Many ionic compounds dissolve easily in...
water
Compared with ionic bonds, covalent bonds are...
weaker
When is energy given off by most nonmetals?
when they gain electrons
How are acids that have been dissolved in water able to conduct an electric current?
They form ions in water, so they conduct an electric current.
What is the force of attraction that holds atoms or ions together called?
chemical bond
an interaction that holds two atoms together
chemical bond
the joining of atoms to form new substances is called
chemical bonding
Table salt is formed when an electron is transferred from a sodium atom to a
chlorine atom
Charged particles that form when atoms gain or lose electrons are
Ions
What ending is used for the names of negative ions?
-ide
A sodium ion has a charge of
1+
Atoms of Group __ elements give off the most energy when they gain an electron
17
Helium atoms only need ____ valence electrons to have a filled outermost energy level.
2
Why is an atom neutral?
An atom is neutral because the number of electrons in an atom equals the number of protons.
What is the relationship between diatomic molecules and diatomic elements?
Diatomic molecules are made up of two atoms of the same element. Diatomic elements are found in nature as diatomic molecules.
The chemical symbol for a sodium ion is
Na+
When an ionic compound dissolves in water, why can it conduct an electric current?
The ions are charged and are able to move freely past one another
Why doesn't sugar dissolved in water conduct an electric current?
The molecules of sugar are not charged.
Why are ions charged particles and thus no longer neutral?
The negative charges and positive charges no longer cancel out, so the atoms become ions.
When does an ionic bond form between a metal and a nonmental?
The number of electrons lost by the metal atoms equals the number gained by the nonmetal atoms.
What does it mean if a substance is not soluble in water?
They do not dissolve well in water
Because strong ionic bonds hold ions together, ionic compounds have...
a high melting point
Ionic compounds tend to be brittle solids
at room temperature
How can you determine the number of electrons in an atom?
atomic number
number of protons in an atom
atomic number
When an ionic compound is hit, the pattern shifts, ions repel each other and the crystal...
breaks apart
A transfer of electrons between atoms changes the number of electrons in an atom, but the number of _______ stays the same
protons