TODAY’S AGENDA Monday 1/5 Welcome Back! FTF What do you KNOW about Atoms? 1) How many parts are there in an Atom? 2) Can you name them? 3) Describe something unique about the parts of an atom. 4) What does an atom look like? (draw a picture) TODAY IN SCIENCE CLASS 1.FTF 2.Bill Nye Atoms 3.Close Reading Activity SWBAT – Identify the parts and charges within an Atom. Homework:

Close Reading Activity  Underline or circle items that you think are important to know.  Make notes in the margins.

TODAY’S AGENDA Tuesday 1/6 FTF 1) Name the 3 parts of an atom. 2) What part has a positive charge? Negative? Neutral? 3) Where in an atom are the protons and neutrons found? 4) Where are the electrons found? 5) Can you draw an atom? TODAY IN SCIENCE CLASS 1.FTF 2.Atoms Textbook Reading & Notes 3.Atoms Hands-On Activity 4.Atoms Foldable for binder SWBAT – List the 3 parts of an atom and identify the charge of all 3. Homework: Atomic Change and “On the Inside” worksheet

INSIDE AN ATOM

Structure of an Atom  An atom is the smallest part of an element.  Scientists know atoms are made up of even smaller particles. READ page in the book. Stop at the checkpoint. Answer the checkpoint at the top of your notes!

Structure of an Atom  The nucleus is the tiny, central core of an atom.  It contains protons and neutrons.  Protons have a positive electric charge. (+)  Neutrons have no charge; they are neutral.  Electrons move in the space around the outside of the nucleus.  Electrons are very energetic.  They move in all directions  Have a negative charge. (-)

A proton is almost 2,000 times as massive as an electron. Neutrons have about the same mass as protons.

Structure of an Atom  In an atom, the number of protons equals the number of electrons.  The total positive charge and negative charge balance making the atom neutral.  The number of neutrons may be the same, but not always.  Count the number of electrons and protons in the rings on the atoms to the left.  What do you notice about the number of protons and electrons in an atom?

Test Your Knowledge  How many protons would be in the nucleus of these atoms? Write your answer in your notes.  Did you say 6 and 18? Great Job! ??

Make Your Own Nucleus  Use the green and orange circles to represent the protons and neutrons of an atom.  The atomic # is equal to the number of protons in an atoms nucleus.  Using the neutron and proton circles, on your desk make a nucleus for  Carbon (atomic # is 6 and there are 6 neutrons)  Calcium (atomic # is 20 and there are 21 neutrons)  Aluminum (atomic # is 13 and there are 14 neutrons)  Draw ONE of the above models in your notes!

Electrons in an Atom  Electrons move around the nucleus so fast it is impossible to know where any electron is at any particular time.  You can think of the space around the nucleus as a “cloud” of negatively charged electrons.

TODAY’S AGENDA Wednesday/Thursday 1/7 & 1/8 FTF (homework out please!) 1) Complete the Atoms Foldable and tape or staple into your binder. TODAY IN SCIENCE CLASS 1.FTF 2.Review homework 3.Finish Notes & Hands On Activity with Electrons 4.BrainPop Quiz SWBAT – List the 3 parts of an atom and identify the charge of all 3. Homework: Bring earbuds/headphones tomorrow!

Atom Mass and Volume  Most of an atom’s mass comes from its protons and neutrons.  Most of an atom’s volume is the large space in which the electrons move.

Valence Electrons  An atom’s electrons are not all the same distance from the nucleus.  The electrons that are farthest away from the nucleus and are involved in chemical reactions valence electrons.  Only valence electrons are involved in chemical bonding.  8 is the highest possible number of valence electrons.

Make Your Own Atom  Now try to create a model of a complete atom using the electrons, neutrons and proton circles.  Nitrogen (atomic # is 7 and there are 7 neutrons)  Sulfur (atomic # is 16 and there are 16 neutrons)  Sodium (atomic # is 11 and there are 12 neutrons)  Remember There should be the same number of protons and electrons. The protons and neutrons go in the nucleus. The electrons circle in “clouds” or “shells” a far distances from the nucleus.  Draw ONE of the above models in your notes

How many valence electrons are in this Carbon atom?

Valence Electrons  A way to show the number of valence electrons that an atom has is an electron dot diagram.  It includes the element symbol surrounded by dots.  Each dot stands for one valence electron.

Let’s Practice  Draw a valence electron diagram for the following elements  Helium He (2 valence electrons)  Oxygen O (6 valence electrons)  Aluminum Al (3 valence electrons)  Argon Ar (8 valence electrons)  Nitrogen N (5 valence electrons)

Why Atoms Form Bonds  A neutral atom never has more than 8 valence electrons.  Most kinds of atoms have fewer.  2 things happen when atoms form bonds:  The number of valence electrons increases to a total of 8.  All the valence electrons are given up.

Why Atoms Form Bonds  When atoms end up 8 or 0 valence electrons, they become less reactive. (Chemically Stable.)

Why Atoms Form Bonds  A chemical bond forms between 2 atoms when valence electrons move between them.  Electrons may be transferred from one atom to another, or they may be shared between the atoms.  Either way, the atoms become bonded  Reactions occur when atoms are bonded or bonds are broken.

Models of Atoms  Dalton Model: 1808  Dalton explained that each element is made of small atoms.  Dalton imagined atoms as tiny, solid balls with different elements have atoms of different mass.

Models of Atoms  Thomson Model: 1897  Thomson suggested that an atom is a positively charged sphere with electrons embedded in it.  His model was described as looking like a muffin with berries scattered throughout.

Models of Atoms  Nagaoka Model: 1904  Japanese physicist, Nagaoka, proposed a model of an atom that had a large sphere in the center with a positive charge.  His model showed the electrons revolving around the sphere like the sun.

Models of Atoms  Rutherford Model: 1911  Rutherford concluded that the atom is most empty space.  Electrons orbit randomly around a small, positively charged nucleus.

Models of Atoms  Bohr Model: 1913  Bohr determined that electrons aren’t randomly located around the nucleus.  This model showed electrons moving in specific layers, or shells.  Bohr stated that atoms absorb or give off energy when electrons move from one shell to another.

Bohr Model

Models of Atoms  Chadwick Model: 1932  Chadwick discovered the neutron, a particle having the same mass as the proton but with no electrical charge.  The existence of the neutron explained why atoms were heavier than the total mass of their protons and neutrons.

Models of Atoms  Modern Model: 1920’s-Present  The current model of an atom came from the work of many scientists from the 1920’s-present.  It shows the electrons forming a negatively charged cloud around the nucleus.

Quantum Model (currently accepted)