The Atom!

GLE 0807.Inq.5 Communicate scientific understanding using descriptions, explanations, and models. GLE 0807.T/E.2 Know that the engineering design process involves an ongoing series of events that incorporate design constraints, model building, testing, evaluating, modifying, and retesting. GLE Explain that matter has properties that are determined by the structure and arrangement of its atoms. GLE Identify factors that influence the amount of gravitational force between objects.

Key concepts: Describe some experiments that led to the current atomic theory Describe the size of an atom. Name the parts of an atom. Describe the relationship between numbers of protons and neutrons and atomic number

Key Vocabulary: Element Proton Neutron Electron Atomic Number Mass number Isotope Atomic Mass

An atom, the review: An atom is the smallest particle into which an element can be divided and still be the same substance All atoms are PURE! Atoms are very SMALL! Parts of the atom? – Nucleus – Electron clouds What does pure mean? What do you already know about atoms?

History Lesson: all based on improvements in technologies and experiments Democritus Heisenberg Schrodinger Bohr Rutherford ThompsonDaltonAristotle Can’t be cut = atom Thought that it could be cut smaller and smaller All matter is made up of atoms; atoms join to make new Discovered electrons; smaller part to atoms Positive center called nucleus Thought electron moved along paths Exact paths can’t be predicted; electron cloudselectron clouds

How has technology changed what we know about science? – Write on the post-it note on your desk. List 3 things that you think have changed as technology has improved? Medicine? History or war?

Review time! Draw this please!

Parts of the atoms: RETAKE! What parts of the atoms are the biggest? Smallest? How many on each ring? Why do we need a model? Number of Protons is equal to the number of electrons! SO, atoms are neutral! If charges are different = ion!

Understanding Periodic table (prequel): Number of protons in the nucleus Remember only 1 capital letter; originals based in Latin (Fe = ferrous which is iron) Number of electrons Weighted average of the masses of all the naturally occurring isotopes of that element Sum of the protons and neutrons in an atom; electrons not included! WHY?

Isotopes Most hydrogen atoms only have a proton in their nucleus. However, about one hydrogen nucleus out of 10,000 also has a neutron. The atomic number of this atom is 1, so the atom is still hydrogen. The nucleus has two particles, a proton and a neutron. This nucleus has a greater mass than a hydrogen atom that has only a proton in it. Atoms that have the same number of protons but a different number of neutrons are called isotopes. The two hydrogen atoms in the figure on the next page are isotopes of each other. They are both hydrogen because each has only one proton. Because they have a different number of neutrons, they have different masses. What are isotopes? What are properties of isotopes? What do isotopes change about an atom? Atoms that have the same number of protons but a different number of neutrons are called isotopes. element with isotopes are the same because they will have the same number of protons. Because they have a different number of neutrons, they have different masses.

Isotopes Most hydrogen atoms only have a proton in their nucleus. However, about one hydrogen nucleus out of 10,000 also has a neutron. The atomic number of this atom is 1, so the atom is still hydrogen. The nucleus has two particles, a proton and a neutron. This nucleus has a greater mass than a hydrogen atom that has only a proton in it. Atoms that have the same number of protons but a different number of neutrons are called isotopes. The two hydrogen atoms in the figure on the next page are isotopes of each other. They are both hydrogen because each has only one proton. Because they have a different number of neutrons, they have different masses. What are properties of isotopes? Word Help: structure the way in which a whole is put together Properties: Isotopes of an element share the same chemical and most of the same physical properties. Can be unstable Can be radioactive Fall apart over a certain amount of time

Forces: Forces of atoms: – Force is a push or pull between objects GRAVITATIONAL FORCE – Gravitational force pulls objects toward one another STRONG FORCE – The strong force holds the nucleus together. WEAK FORCE – weak force is important in radioactive atoms. In certain unstable atoms, a neutron can change into a proton and an electron. ELECTROMAGNETIC FORCE – objects with like charges to repel each other – objects with opposite charges to attract each other. – Protons and electrons are attracted to one another because of the electromagnetic force. What would happen if these forces did not exist? Page 272

Review: What is the atomic theory? How has the atomic theory changed over time? What are the parts of an atom? How do atoms of different elements differ? What are isotopes? What forces work inside atoms?

Pearls of Wisdom: Atomic theory has changed over time. Atoms are extremely small. Ordinary-sized objects are made up of very large numbers of atoms. Atoms consist of a nucleus, which has protons and usually neutrons, and electrons, located in electron clouds around the nucleus. The number of protons in the nucleus of an atom is that atom's atomic number. All atoms of an element have the same atomic number. The forces at work in an atom are gravitational force, electromagnetic force, strong force, and weak force.

ACTIVITY TIME! FOR THIS ACTIVITY, DO NOT WRITE OR CUT OUT THE SHEET. YOU WILL DO THIS ON YOUR OWN PAPER OR YOU MAY HAVE SOME OF MINE. YOU CAN WORK WITH THE PERSON SITTING CLOSEST TO YOU! OR ALONE! THIS WILL GO INTO YOUR NOTEBOOK.

Homework: Workbook: – As you read the section tonight, do pages Workbook: – As you read the section tonight, do pages