Energizer What are the 3 main particles within the atom? List everything you know about each of these.

Unit 1 Part 3 The history of the atomic model The structure of the atom Reading the periodic table

What is an atom made of? Protons +1 Charge 1 amu (atomic mass unit) 1amu=1.7 * g Neutrons 0 (neutral) charge 1amu Electrons -1 Charge Found around the nucleus in an electron cloud Virtually no mass The protons and neutrons are located within the nucleus. It has very little volume but almost all of the mass of the atom so it is VERY dense!

What is the Charge of an Atom? In a typical atom you will have the same number of protons and electrons, what charge does this give the atom? 0 Charge, or it is neutral!

Can a proton leave an atom?? No If it did you would have a NEW element…more on this later!

Can an electron leave or join an atom?? Yes! This is called an Ion If the atom is missing an electron it will be a Positive Ion. If the atom gains and electron it will be a Negative Ion.

Can the number of neutrons change? Yes! This is called an isotope, it will cause the MASS of the atom to change

Reading the Periodic Table Each element’s properties can be determined by the information in its “box” as well as its placement on the Table See pages 768/69 to review the information!

What’s in The Box? Element Symbol Zr is Zirconium Atomic Number- tells the number of protons in one atom of the element Zr has 40 Protons (therefore it also has 40 electrons) Atomic Mass (Mass Number) Tells number of protons and neutrons combined (40 + ? = 91)

You Try… My atomic number is 51, my name is…  Antimony My atomic mass is 39.95, my name is…  Argon My atomic mass is , my name is…  Tungsten My atomic number is 102, my name is…  Nobelium

Some more… My name is Sulfur and I have this many protons  16 My atomic number is 19, this is my name and how many electrons I have  Potassium, 19 electrons My name is Cadmium, I have this many protons and neutrons combined  112

Elements And Their Atoms Each element has a unique atomic number The number of protons for an element’s atom is constant and unique The number of electrons will equal the number of protons UNLESS the atom is an ion An element’s atom can have a different number of neutrons Since the mass of an atom depends on the protons and neutrons, the mass of an element can change To find neutrons, subtract the atomic # from the atomic mass

For Example… Look at the periodic table and find Carbon What is the atomic number? What is the mass number? “Carbon 12” is the most common form of Carbon But you’ve heard of Carbon 14…That is an isotope of Carbon – it has two more neutrons, adding 2 amu to its mass…but it still has only 6 protons To name an Isotope Element Name – Mass #

Isotope of Different Element Element D has 6 protons and 7 neutrons Element F has 7 protons and 7 neutrons Different Element Element J has 27 protons and 32 neutrons Element L has 27 protons and 33 neutrons Isotope Element T has an atomic number of 20 and an atomic mass of 40. Element Z has an atomic number of 20 and an atomic mass of 41. Isotope

Forces In The Atom Gravitational Force Attractive force between all objects in the universe Gravity depends upon mass of and distance between objects… This force is not very strong in the atom Electromagnetic Force Opposites attract; likes repel Protons & electrons Electrons and Nucleus

More Forces in the Atom Strong Force (the physicists got original naming this one) Holds protons and neutrons together to make the nucleus Greater than electromagnetic force between protons (since the protons would repel each other) Weak Force – Yes, it’s a very weak force Deals more with radioactive decay and nuclear fusion

The Periodic Table Columns are called groups or families, and as family members, they have similar properties Rows are called periods. They do not share properties, but properties change as one goes from left to right

The Periodic Table

The first element in a period is always an extremely active solid. The last element in a period is always a particularly inactive gas. These are referred to as the “noble gases.”

Warm Up Using the periodic table, draw what you think a model of an atom of oxygen would look like You should have 8 protons and 8 neutrons in the nucleus, and 8 electrons surrounding the nucleus.

Warm Up – November 2 nd Find the Mystery Element Find the atomic number of Hydrogen and add to it the atomic number of Beryllium; Multiply Lithium’s atomic number by the answer in step 1; Add five and divide by the atomic mass of Helium; Add four to the answer in step 3; The result is the atomic number of this element… Fluorine

Find the Mystery Element Multiply the protons of Lithium by the neutrons of Boron; Add the electrons of Carbon; Divide by the atomic number of Magnesium; Add the protons of Arsenic; Divide by the mass number of Lithium The result is the atomic number of this element… Boron, Atomic number

Another Mystery Element Multiply the atomic number of Beryllium by the number of protons in Neon; Subtract the atomic number of Carbon; Add the number electrons of Helium; Divide by the number of protons in Fluorine; Subtract the number of electrons in Lithium; The result is the atomic number of this element… Hydrogen