Atoms and the Periodic Table

Bell work

RESPOND TO THE FOLLOWING:

List the subatomic particles, their charges, locations, and relative masses.

How do you determine the number of protons and electrons? How do you calculate neutrons?

The Periodic Table

objectives:

• Learn patterns of the periodic table that can be used to create models of atoms.

• Learn how elements combine, depending upon their properties, to form molecules and compounds.

Vocabulary - copy

• atomic number = the number of protons (also equal to number of electrons)

• atomic mass = the number of protons plus neutrons

• energy levels - where the electrons are outside the nucleus (the first energy level can hold up to 2 electrons, the second and third energy levels can hold up to 8 electrons)

• valence electrons - the electrons in the outer energy level

• bonding - when electrons are shared or transferred to gain stability

• molecules - have two or more atoms

• compounds - have two or more elements

Atomic # & Mass #

• Atomic number is a whole number.

• It is equal to the number of protons.

• It is also equal to the number of electrons.

• Mass number is not a whole number.

• It is equal to the number of protons and neutrons.

Multiple Choice

How many protons and electrons does Lithium (Li) have?

• 3 of each.

• 6 of each.

• 7 of each.

• 3 protons. 7 neutrons.

Calculating the Number of Neutrons

# of Neutrons =

Mass number - (minus)

Atomic number

for example, for Sodium (Na),

23-11=12

Sodium has 12 neutrons.

Patterns

• Elements are arranged by increasing atomic number.

• The group (AKA family) number (labeled with a Roman numeral above each column) is equal to the number of electrons found in each valence. 

• Every element in group one has one electron in its outer shell (valence). Every element in group two has two electrons in its valence. etc. 

Multiple Choice

How many valence electrons does Flourine (FL) have?

• 1

• 5

• 7

• 9

Multiple Select

The number of valence electrons for an element is equal to . . .

• the mass number

• the atomic number

• the mass number minus the atomic number

• the group or family number

Multiple Select

The periodic table is organized by . . .

• mass number

• atomic number

• valence number

• group or family number

Multiple Choice

Flourine (Fl) is in group VII. How many valence electrons does it have

• 1

• 4

• 7

• 8

Patterns

• Elements with valences that are not full are more reactive, and more likely to share or transfer their electrons

• Only Family (Group) 8 elements have their valences full. They are the noble gases.

• Other groups' elements need to gain or lose electrons to fill their valences. They are reactive.

Multiple Choice

Which element is most reactive:

Lithium from Group I

OR

Neon from Group VIII?

• Lithium

• Neon

Patterns

• The row number corresponds to the number of energy levels for the elements that row.

• For example, the elements in the top row have one energy level. The first energy level can hold up to two electrons.

• The second row elements have two energy levels. The third row elements have three energy levels. The 2nd and 3rd energy levels can hold up to 8 electrons.

Multiple Choice

Helium has an atomic number of 2. How many energy levels does hydrogen have? Is its valence full?

• one, yes

• one, no

• two, yes

• two, no