Atoms

1. Atoms

2. Vocabulary • Atomic # • Proton • Neutron • Electron • Isotopes • Mass # • Model

3. Protons, neutrons, and electrons

4. Nucleus-the central part of the atom, is made from protons and neutrons.

5. What is the atomic # What is floating around the nucleus? What particles make up nucleus?

9. Because atoms are so small, scientists create models to describe them. • Models may be a diagram, mental picture, mathematical statement, or an object that helps explain ideas about the natural world MODELING ATOMS

12. Identifying Numbers • Atomic number- the number of protons in the nucleus of an atom • Atomic Mass-the number of protons and neutrons in the nucleus of an atom.

14. Number of Neutrons • Isotopes-are atoms of the same element that have different numbers of neutrons. • Ex-Carbon-12, Carbon-13 and Carbon-14

16. Carbon Isotopes • Carbon-12 has 6 protons, 6 neutrons, and 6 electrons • Carbon-13 has 6 protons,, 7 neutrons, and 6 electrons • Carbon-14 has 6 protons, 8 neutrons, and 6 electrons.

17. Use of radioactive isotopes • Isotopes are used in the medical field • Ex-Iodine-131 is used to diagnose thyroid problems. It is injected into the patient and shows up in x-rays as it goes through the body. • Isotopes are also used in the environment. These are placed in fertilizers, pesticides etc.

21. Strong Nuclear Force • The force that holds protons together in the nucleus of an atom. • This force is what keeps the positive force of protons from pushing each other apart. This works because the protons are packed so tightly together.

22. Radioactive Decay • The release of nuclear particles and energy from an atom. • Only unstable atoms-atoms with a different number of neutrons than protons, undergo radioactive decay. • The changing on one element into another through radioactive decay is transmutation.

23. Vocabulary Atomic mass Periodic table Chemical symbol Period group

24. Patterns in the Elements 63 elements discover in 1869, Mendeleev discovered a set of patterns that applied to all the elements Atomic mass= average mass of all isotopes for that element He noticed pattern as he arranged the elements by the increasing atomic mass Mendeleev’s work Found properties repeated and he placed them in groups together Mendeleev's Periodic table Predicting new elements • Found arrangement by mass did not always group them by similar characteristics • Left blank spaces for undiscovered elements • Published in 1869 first table

25. Modern periodic table Periodic table- chart of the elements showing the repeating pattern of the chemicals and the properties Period-a row (periodic means regular repeating pattern) Rearranged by atomic # Finding Elements Square (key) includes the atomic #, symbol, Atomic mass, and name Atomic Number (#) Tells you the number of protons

26. Chemical symbols and names Contains either one upper case letter (K) or one upper case and a lower case (Na) taken from their Latin names Average Atomic mass The last number in key is an average because most elements have isotopes and it is the combined percentage of all of their weights Organization of the Periodic Table • Arranged by atomic number • Properties of an element may be predicted from its location on the table Periods 7 horizontal rows (like the days of the week) Groups 18 Vertical columns, known as families, have similar characteristics

27. Section 2 • Mendeleev- Discovered elements had a pattern to their properties when he arranged them by increasing atomic mass. • He formed the first periodic table • Left blanks and predicted that new elements would fill those spots

28. Today’s table • Properties of elements may be predicted by their placement on the periodic table. • Arranged by atomic number • 18 columns called groups/families have similar characteristics • 7 rows called periods

29. Atomic Mass • Average of all the atomic weight of the isotopes and the elements • This is why it is a decimal number and not whole #

30. Definitions • Atomic mass • Periodic table • Chemical symbol • Period • Group

31. Valence Notes from movie- valence electrons- ones in the outer shell Orbital and electron shells same

32. Now let’s talk more about electrons and where they are found!!!! Orbitals...

33. Electrons are part of what makes an atom an atom But where exactly are the electrons inside an atom? atom

34. Orbitals are areas within atoms where there is a high probability of finding electrons.

35. Knowing how electrons are arranged in an atom is important because that governs how atoms interact with each other

36. Knowing how electrons are arranged in an atom is important because that governs how atoms interact with each other

37. Knowing how electrons are arranged in an atom is important because that governs how atoms interact with each other

38. Let’s say you have a room with marbles in it The marbles are not just anywhere in the room. They are inside boxes in the room.

39. You know where the boxes are, and you know the marbles are inside the boxes, but… you don’t know exactly where the marbles are inside the boxes

40. The room is an atom The marbles are electrons The boxes are orbitals

41. The room is an atom The marbles are electrons The boxes are orbitals Science has determined where the orbitals are inside an atom, but it is never known precisely where the electrons are inside the orbitals

42. An interesting place where electrons have a specific organization within atoms, allowing for interesting atom interactions

43. (does not actually exist) Not an interesting place, where electrons have no specific organization within atoms, where atoms wander aimlessly about An interesting place where electrons have a specific organization within atoms, allowing for interesting atom interactions

44. The Periodic Table

45. Characteristics of Metal • Malleable—a material that can be hammered or rolled, coins (ex. Gold, magnesium, aluminum) • Ductile—a material that can be pulled out, wire • (ex. Gold, magnesium, aluminum) • Conductivity—ability to transfer heat or electricity • Luster- shiny • Octet rule—states that atoms tend to combine in such a way that they each have eight electrons in their valence shells

46. Alkali Metals • Alkali metals—Group 1, the alkali metals are all highly reactive and are never found in elemental forms in nature, one electron in their outmost electron shells • Alkali metals—Group 1, the alkali metals are all highly reactive and are never found in elemental forms in nature, one electron in their outmost electron shells

47. Alkaline Earth Metals • Alkaline earth metals—Group 2, insoluble in water and resistant to heating, two electrons in their valence shell http://www.youtube.com/watch?v=ogf726TgczA&edufilter=DQBPVNZ5nlfNZmzO0OgIrQ

48. Transition Metals • Transition metals—Groups 3-12, characteristics include hard and shiny, good conductors

49. Earth Metals • Earth metals—Group 13-15 below the steps, not very reactive

50. Metalloids • Metalloids—along the border between metals and nonmetals, have characteristics of both