Intro to Chemistry: Atoms and the Periodic Table Unit 7 – Part A

The Universe is Made of Two Things: 1.Matter (The Stuff). 2.Energy (What moves the stuff).

Chemistry: Chemistry is the study of matter and change. Matter is something that has mass and takes up space, “stuff”

What is Matter Made of? Matter Matter is made up of elements and compounds. Elements are any material that is made up of one single type of atom. A gold brick – only gold atoms A gold brick – only gold atoms Graphite pencil – only carbon atoms. Graphite pencil – only carbon atoms. Elements are listed on the Periodic Table

Naming Elements Atomic Symbol designates each element. Comes either from the first letter (1 st two letters) of the element or from the element’s Latin name. Comes either from the first letter (1 st two letters) of the element or from the element’s Latin name. Carbon = C Gold = Au (aurum) First letter is always capitalized. First letter is always capitalized. First direct evidence of atoms was discovered by Robert Brown in Brownian motion Brownian motion

Elements combine with each other to form compounds O H O H H O H H O H H H

H H O Element? Compound? Both? Ne Kr H H O C O O Na Ne Cl

Atoms’ Empty Space Like charges repel, keeping space in- between atoms Electrons on the outer shell of the atom produce a charge. Electrons on the outer shell of the atom produce a charge. Electrical repulsions prevent you from passing through walls and through your seat. Electrical repulsions prevent you from passing through walls and through your seat.

The Atoms’ Make-up Proton – particle found in the atomic nucleus and carries a positive charge. Neutron – particle found in the atomic nucleus and carries no charge. Electron – tiny particle surrounding the nucleus and carries a negative charge.

The Atoms’ Make-up Atomic number represents the number of protons contained in each atomic nucleus. Elements are listed in order of increasing atomic numbers. Elements are listed in order of increasing atomic numbers. Hydrogen = H = 1 Hydrogen = H = 1 Helium = He = 2 Helium = He = 2 Lithium = Li = 3 Lithium = Li = 3 Beryllium = Be = 4 Beryllium = Be = 4

The Atoms’ Make-up Every element has a definite number of protons, but the number of neutrons it contains may vary. Atoms of the same element that contain different numbers of neutrons are isotopes. Atoms of the same element that contain different numbers of neutrons are isotopes.

The Atoms’ Make-up We identify isotopes by their mass number, the total number of protons and neutrons they contain. Hydrogen isotopes: Hydrogen isotopes: H-1 = only 1 proton H-1 = only 1 proton H-2 = 1 proton and 1 neutron H-2 = 1 proton and 1 neutron H-3 = 1 proton and 2 neutrons H-3 = 1 proton and 2 neutrons Atomic mass represents the sum of the masses of all the atom’s components.

How Does Matter Change? Does matter always stay the same?

Matter Doesn’t Always Stay The Same:

How Does Matter Change? 1.Physical change: O H moves atoms or compounds around, but doesn’t break or make any bonds between atoms H O H H O H H O H H How would you be able to tell a physical change happened?

-may change shape, size, or phase (solid, liquid, or gas) -Usually easy to undo

2. Chemical change: O H O H H O H H O H Makes and/or breaks bonds between atoms How would you be able to tell a chemical change happened?

- may change color, change smell, release or absorb energy, or release a gas - substance turns into something else (difficult to undo) - aka, a chemical reaction

Physical or Chemical change? Ne C O O O O C

Physical or Chemical change? Baking soda is added to vinegarSugar is added to water

Physical or Chemical change? Water in the cracks of a rock freezes, breaking the bedrock Acids in the “roots” of a lichen growing on a rock slowly dissolve the rock over time

Elements Organized by Their Properties

Metals: shiny, opaque, and good conductors of electricity and heat. Malleable and ductile Malleable and ductile Most are solid at room temperature. Most are solid at room temperature.

Elements Organized by Their Properties Nonmetals: poor conductors of electricity and heat, and may also be transparent. Solid nonmetals are neither malleable nor ductile. Solid nonmetals are neither malleable nor ductile.

Elements Organized by Their Properties Metalloids: have both metallic and nonmetallic characteristics. Boron, Silicon, Germanium, Arsenic, Tin, and Antimony. Boron, Silicon, Germanium, Arsenic, Tin, and Antimony.

Period and Group Organization

Periods are horizontal rows in the periodic table. (7 total) Groups are vertical columns in the periodic table. (18 total) Elements in the periodic table gradually change and is called a periodic trend.

Identify & Define Groups You and your group will select one of the following groups and collect information: Alkaline Metals, Alkaline-Earth Metals, Transition Metals, Inner Transition Metals, Chalcogens, Halogens, & Noble Gases. Alkaline Metals, Alkaline-Earth Metals, Transition Metals, Inner Transition Metals, Chalcogens, Halogens, & Noble Gases. Develop a two (2) minute presentation to define, give examples, and give important information to the class about your group.

Identify & Define Groups Alkaline Metals: Group 1 elements, history links properties for the preparation of soaps. Group 1 elements, history links properties for the preparation of soaps. Lithium, Sodium, & Potassium. Lithium, Sodium, & Potassium. Alkaline-Earth Metals: Group 2 elements, do not melt or change when placed in fire, “fire-resistant”. Group 2 elements, do not melt or change when placed in fire, “fire-resistant”. Magnesium, Calcium, & Strontium. Magnesium, Calcium, & Strontium.

Identify & Define Groups Transition Metals: Group 3-12 elements, do not form alkaline metals and tend to be harder and used for structural purposes. Group 3-12 elements, do not form alkaline metals and tend to be harder and used for structural purposes. Iron, Copper, Nickel, Silver, & Gold. Iron, Copper, Nickel, Silver, & Gold. Inner Transition Metals: In the 6 th and 7 th element groups. In the 6 th and 7 th element groups. Lanthanides (associated with LED screens) Lanthanides (associated with LED screens) Actinide (Uranium & Plutonium) Actinide (Uranium & Plutonium)

Identify & Define Groups Chalcogens: Group 16 elements, derived from the term “ore-forming”. Group 16 elements, derived from the term “ore-forming”. Oxygen & Sulfur. Oxygen & Sulfur.Halogens: Group 17 elements, derived from the term “salt-forming” and associated with cleaning. Group 17 elements, derived from the term “salt-forming” and associated with cleaning. Chlorine, Bromine, & Iodine. Chlorine, Bromine, & Iodine.

Identify & Define Groups: Noble Gases: Group 18 elements, all unreactive gases that tend not to combine with other elements. Group 18 elements, all unreactive gases that tend not to combine with other elements. Helium, Neon, Argon, & Xenon. Helium, Neon, Argon, & Xenon.

What is an Atom?

What in the world is the world made of?? Atom - the basic unit of matter - the smallest particle Just how small are they?

Video: Just how small is an atom? Video: Just how small is an atom?

Are atoms the smallest thing? Subatomic particles - the parts inside an atom

The 3 Subatomic particles: + - NameChargeMass (a.m.u.) Location Proton+1In the nucleus Neutron01In the nucleus Electron—Almost zero Outside the nucleus in orbitals amu = a tomic m ass u nit