The Periodic Table of Elements and Atoms…

History first… Alchemy Robert Boyle John Dalton Dmitri Mendeleev Jons Berzelius

Alchemy: one of the earliest forms of chemistry. Scientists try (unsuccessfully) to turn metals of low value (iron or lead) into gold. Though they were unsuccessful, they contributed knowledge to the chemical world. For example how changes affect matter.

Robert Boyle… Considered the first real chemist. He introduced the first definition of an element as a pure substance that cannot be broken into simpler substances by chemical means.

John Dalton… introduced the idea that each element was made up of a different kind of atom.

Atomic Structure… An atom is made up of three basic parts: protons, neutrons, and electrons. The protons which have a positive charge [+] and the neutrons which have no charge, form the nucleus in the center of the atom. The electrons which have a negative charge [-], move sporadically around the nucleus.

Draw this model on your paper

Electrons are negatively charged particles that have a very low mass. There are an equal number of electrons as there are protons. Protons are positively charged particles found in the nucleus. There are an equal number of protons as there are electrons.

Neutrons, also found in the nucleus, have no electrical charge. They are neutral. They have about the same mass as a proton. The nucleus is the central core of an atom that contains most of the mass of an atom because it contains both the neutrons and protons.

Each atom has an equal number of protons and electrons. Because the negative charge of the electrons balances the positive charge of the protons, atoms are neutral.

Dmitri Mendeleev… arranged the elements into a systematic chart or table called the Periodic Table of Elements. Today’s periodic table of elements based on Mendeleev’s version groups the elements by similar properties. It gives the symbol, the atomic number, and the atomic mass of each element.

Jons Berzelius… introduced a system of abbreviation for the elements, which is still in use today. The symbol was determined by using the first letter of the element’s name or Latin name and capitalizing it and in most cases added another letter, which remained lower case.

1 H Hydrogen Atomic Number-tells you the amount of protons and electrons. Atomic Symbol Full Name Atomic Mass An example of how an atom is represented on the Periodic Table of Elements.

How do you know how many protons, electrons, and neutrons each atom has? The atomic # tells you how many protons and electrons there are in each atom. You need a formula to calculate the amount of neutrons. The formula is: Atomic mass(large #) minus the Atomic #(smaller #) equals the amount of neutrons. or AM – A# = neutrons

Practice finding the amount of Protons, Electrons, and Neutrons: 1.Aluminum 2.Oxygen

Practice continued 3. Mercury 4. Hydrogen

The Periodic Table of Elements Each box on the table represent an atom. Start seeing each element as a different atom. The boxes are arranged in order of increasing atomic number (protons/electrons) as you move from left to right. The boxes are arranged into a grid of periods (Horizontal rows) and groups (Vertical columns)

Two different numbering systems! One of the numbering systems: –Numbers the groups(columns) 1-18! The other numbering system: –Divides the table of elements into two categories: Main Group Elements- the first two groups(columns) and last six groups(columns). We notate the group number with the letter “A”. (Ex., 2A) Transition Metals-the ten groups(columns) in the center. We notate the groups number with the letter “B”. (Ex., 3B)

List the numbers as they would appear at the top of each column on the P.T.o.E.: 1_ 2_ ___ ___ ___ ___ ___ __ ___ ___ ___ ___ ___ ___ ___ ___ ___ ___ _1a_ 2a_ ___ ___ ___ ___ ___ __ ___ ___ ___ ___ ___ ___ ___ ___ ___ ___

Let’s talk organization! The elements are divided into 3 categories: Metals, Metalloids, and Nonmetals. We use the “Zig-Zag” line as a reference.

The metals are to the left of the “Zig-Zag” line except: Hydrogen-it’s a nonmetal The metalloids are on the “Zig-Zag” line. except: Aluminum, it’s all metal! The nonmetals are to the right of the “Zig-Zag line. except: Hydrogen-even though it is located to the left it is still a nonmetal

Memorizing the states of each atom at room temperature helps use the periodic table as a tool! There are 11 gases and 2 liquids at room temperature: hydrogen- Helium- Nitrogen Oxygen Fluorine Chlorine Neon Xenon Argon Krypton Radon Gases Bromine Mercury Liquids

The six gases located in the group #18(8a) are called the noble gases. These gases are different and set apart from other gases because they do not combine easily if at all with other atoms/elements.

Acids and Bases to be discussed on Bonding Notes!!!

The End I hope you enjoyed!!!