Periodic table
The Group A number tells us what about an element?
The number of valence electrons in each atom
The smallest particle of an element that is identifiable:
an atom
List the three subatomic particles
Protons, Neutrons, Electrons
What kind of change occurs when food is chewed up and digested?
a physical and a chemical change.
Identify the element with the atomic number of 31
The period an element is found in tells us what?
The number of energy levels found in the electron cloud of each atom.
Two or more atoms chemically bonded together
molecule
Protons and electrons
List the 5 signs of a chemical reaction
Change in color, change in temperature, change in other properties, formation of a precipitate, and production of a new gas.
How many electrons does gallium have and why?
31, because atoms are theoretically neutral and it has 31 protons.
What four pieces of information are listed in each element's square on the periodic table?
Name, symbol, atomic number and atomic mass.
the solid formed when two chemicals in a solution react
Precipitate
Which two subatomic particles are counted to determine the atomic mass?
Protons and neutrons
A chemical reaction that releases energy from chemical bonds is called_________ and can be identified by a _______ in temperature.
exothermic, increase
How many neutrons does gallium have?
39
A mystery element is a good conductor of heat, shiny, solid at room temperature, and malleable. What kind of element is this?
A metal
The number in a chemical equation that is written to the left of a molecule and tells how many of that molecule are involved in the reaction.
coefficient
Counting the number of protons tells us what two pieces of information?
The atomic number and the name (identity) of the element.
Identify the number of atoms of each element involved in the reaction below: Na2SO4 +SrCl2 → 2 NaCl +SrSO4
Na:2 S:1 O:4 Sr:1 Cl:2
Which group of elements is generally considered "nonreactive" or "inert" and why?
Noble gases, because they have a complete valence level.
A mystery element is brittle, dull, and a good conductor of heat and electricity. What kind of element is this?
a substance added to a reaction to allow it to occur with less activation energy
Catalyst
These particles are the most loosely held and determine most of the properties of an atom
Valence electrons
Identify the type of reaction shown: FeBr3 + 3 NaOH → Fe(OH)3 + 3 NaBr
Double displacement
Which two groups of elements are the most reactive and why?
Group 1A and Group 7A, because they only need to add or lose 1 valence electron to get to a complete valence shell