Atoms Elements and the Periodic Table The Periodic

Atoms, Elements, and the Periodic Table

The Periodic Table Periodic means: Repeating according to a pattern The periodic table is arranged in columns and rows Columns go up and down (think of columns on a building) Rows go from left to right

In your Bohr Model What patterns did we see? In each column and row…. Look at the number of Shells & Outer Electrons

The Periodic Table (cont. ) Groups or Families Columns are called: Groups or Families There are 18 groups or families in the periodic table (today you will know four a lot better) Elements in the same group or family have the same number of valence electrons Valence electrons are the number of electrons in the outer most energy level Group 1 has 1 valence electron

The Periodic Table -Periods are the portion of the periodic table that go from left to right (think of when you write a sentence, you put a period at the end of the sentence. There are 7 periods in the periodic table. All elements in the same period, have the same number of energy shells. Energy shells are where the electrons are located

Today you will look more closely at the families in the table

Groups and Families The columns in the periodic table are called groups, or families. Each group has the same number of outer shell electrons Group 1: Alkali Metals Group 2: Alkaline Earth Metals Group 7: Halogens Group 8: Noble Gases

Valence Electrons All elements in a group have the same number of outer shell, or valence electrons Valence electrons determine how an element will behave and what it bonds with How many valence electrons does each group have?

Ion Charge (Ion Formed) You should remember that 8 is great! Elements will either gain or lose electrons to try to have 8 Elements with 3 or less electrons will LOSE electrons Becoming _______ Elements with 4 or more will GAIN electrons Becoming _______ For Hydrogen and Helium, 2 is good too! They can’t possibly hold 8 electrons, so they are full

Atoms are the building blocks of matter The modern atomic model describes an atom as consisting of: Nucleus that contains: Protons, neutrons, and electrons outside of the nucleus

Sub-atomic Particles Subatomic particles: Protons, neutrons, and electrons Each element in the periodic table has its own specific number of protons

Atomic Number The atomic number is the number of protons in an element Every atom of a specific element has the same number of protons Example: Hydrogen has 1 proton Carbon has 6 protons Sulphur has ______ Silver has _______

Neutrons Found in the nucleus Have no charge (neutral)

Isotopes are: Elements having the same number of protons, but different numbers neutrons Examples: Carbon 12, 6 protons+ 6 neutrons Carbon 13, 6 protons+7 neutrons Carbon 14, 6 protons + 8 neutrons

Mass Number Mass number is the number of protons + neutrons in the nucleus of an atom The atomic mass number is the average of the isotopes found naturally. 1 AMU is the weight of a proton/neutron (these particles are almost equal in mass) and each 6000 times larger than an electron

Electrons are found orbiting around the nucleus in electron clouds (we can call them shells) The exact location of electrons cannot be determined Electrons have a negative charge (-) In a neutral atom, the number of electrons= the number of protons

Electrons An atom that has gained or lost electrons is called and ion. Ions carry an electric charge because the number of protons (positive) in them is not equal to the number of electrons (negative. ) The charge on an ion is shown on the symbol of an element by adding a superscript number followed by a plus or minus sign.

Using this information We can make a Bohr model of each element: 1) Write down the atomic mass and atomic number 2) Calculate the number of protons, electrons and neutrons Atomic number = # of protons, and #of electrons in an neutral element Atomic mass – atomic number = the # of neutrons

Bohr models 3) Put the protons and neutrons in a circle to represent the nucleus 4) Fill the electrons into the energy shells 2 electrons fill the first shell 8 electrons fill the second 8 electrons fill the third 18 fill the fourth.