Shared Flashcard Set

Details

Science Test November 2010
Chapter 1 Atoms and Bonding (Book 2)
53
Science
8th Grade
11/08/2010

Additional Science Flashcards

 


 

Cards

Term
Matter
Definition
anything that has mass and takes up space
Term
Elements
Definition
the simples pure substances, and they cannot be broken down into any other substances
Term
Elements are often called
Definition
the building locks of matter because all matter is composed of one element or a combination of two or more elements
Term
compound
Definition
a pure substance made of two or more elements that are combined  chemically in a specific ratio
Term
mixture
Definition
two or more substances-elements, compounds, or both-that are in the same place but not chemically combined
Term
atom
Definition
the smallest particle of an element
Term
scientific theory
Definition
a well-tested idea that explains and connects a wide range of observations
Term
models
Definition
physical, mental, visual, and other representations of an idea to help people understand what they cannot observe directly
Term
Atomic theory grew as 
Definition
a series of models that developed from experimental evidence. As more evidence was collected, the theory and models were revised
Term
electrons
Definition
negatively charged particles
Term
nucleus
Definition
the central core of the atom, containing protons and usually neutrons
Term
protons
Definition
positively charged particles
Term
energy level
Definition
the specific amount of energy an electron has
Term
neutrons
Definition
particle electrically charged neutrally
Term
valence electrons
Definition
those electrons that have the highest energy level and are held most loosely
Term
The number of valence electrons in an atom of an element determines
Definition
many properties of that element, including the ways in which the atom can bond with other atoms
Term
electron dot diagram
Definition
the symbol for the element surrounded by dots (valence electrons). from 1-8, 8 being neutral
Term
chemical bond
Definition
the force of attraction that holds two atoms together as a result of he rearrangement of electrons between them
Term
symbol
Definition
each element is represented by a
Term
atomic number
Definition
the number of protons in the nucleus of atom
Term
period
Definition
a row of elements across the periodic table
Term
group or family
Definition
elements in the same column
Term
As the # of protons-or atomic number- increases, the # of ____ also increases
Definition
electrons. The properties of the elements change in a regular way across a period.
Term
Group 18 elements are known as 
Definition
noble gases
Term
Halogens
Definition
the elements in Group 17
Term
alkali metal 
Definition
an element belonging to Group 1 of the periodic table
Term
ion
Definition
an atom or group of atoms that has an electric charge
Term
When an atom loses an electron
Definition
it loses a negative charge and becomes a positive ion
Term
When an atom gains an electron
Definition
it gains a negative charge and becomes a negative ion
Term
polyatomic ions
Definition
ions that are made of more than one atom
Term
ionic bond
Definition
the attraction between two oppositely charged ions
Term
Ionic bonds form as a result of...
Definition
the attraction between positive and negative ions
Term
ionic compound
Definition
a compound that consists of positive and negative ions
Term
chemical formula
Definition
a combination of symbols that shows the ration of elements in a compound
Term
When ionic compounds form...
Definition
the ions come together in a way that balances out the charges on the ions
Term
The chemical formula for the compound reflects...
Definition
balance
Term
subscript
Definition
tells you the ratio of elements in the compound
Term
For an ionic compound, the name of the _____ ion comes first, followed by the name of the _____ ion
Definition
positive; negative
Term
Ionic Compound Characteristics
Definition
hard, brittle crystals that have high melting points. When dissolved in water or melted, they conduct electricity
Term
crystal
Definition
the ions form an orderly, three-dimensional arrangement
Term
covalent bond
Definition
the chemical bond formed when 2 atoms share electrons
Term
The force that holds atoms together in a covalent bond is..
Definition
the attraction of each atom's nucleus for the shared pair of electrons
Term
molecule
Definition
a neutral group of atoms joined by covalent bonds
Term
double bond
Definition
the two atoms share two pairs of electrons
Term
triple bond
Definition
elements such as nitrogen and carbon
Term
molecular compound
Definition
a compound that is compound of molecules
Term
Compared to ionic compounds, molecular compounds generally have
Definition
lower melting points and boiling points, and they do not conduct electricity when dissolved in water
Term
Atoms of some elements pull more strongly on 
Definition
shared electrons that do atoms of other elements. The electrons are pulled more toward one atom, causing the bonded atoms to have slight electrical charges.
Term
polar bond
Definition
a covalent bond in which electrons are shared unequally
Term
nonpolar bond
Definition
a covalent bond in which electrons are shared equally
Term
metallic bond
Definition
an attraction between a positive metal ion and the electrons surrounding it
Term
alloy
Definition
a material made of two or more elements that has the properties of a metal
Term
The "sea of electrons" model of solid metals explains their ability to
Definition
conduct heat and electricity, the ease with which they can be made to change shape, and their luster
Supporting users have an ad free experience!