Atoms and Molecules
What is the smallest unit of matter that keeps the properties of an element?
ATOM
Atom is the smallest unit of matter that keeps the properties of an element.
What do we call the column (vertical) in the periodic table?
Which has higher electronegativity: fluorine or sodium?
Fluorine
What do we call electrons in the outer shell?
Valence electrons
What do we call the starting materials in a reaction?
Reactants
What do we call two or more atoms joined together?
Molecule
Where are metals located on the periodic table?
Left side
Which bond is more polar: O–H or C–H?
O-H
What type of bond shares electrons?
Covalent bond
What do we call the new materials made?
Products
Which particle has a negative (–) charge in an atom?
Electron
What number tells how many protons an atom has?
Atomic number
Do metals have high or low electronegativity?
LOW
What rule do atoms generally obey to be stable in outer shell?
Octet rule (8 valence electrons)
Name one sign of a chemical reaction.
Gas, color change, temperature change, solid forms
Which particle has a positive (+) charge in an atom?
proton
Elements in the same column (same group) have the same what?
Number of valence electrons
What does electronegativity mean?
How strongly an atom pulls electrons
If two atoms pull electrons equally, what type of bond forms?
Nonpolar covalent
Why do we need to balance equations?
Matter cannot be created or destroyed
What is one difference between a compound and a mixture?
Compound = chemically joined;
Mixture = just mixed
Why do elements in the same group have similar properties?
Same number of valence electrons