Periods and Groups All of the elements in

Periods and Groups All of the elements in a period have the same number of Electron Energy Levels. The elements in a group have the same number of electrons in their outer Electron Energy Level. Slide 1

Metals • Almost 75% of all elements are classified as metals. • CONDUCTION: – Metals are really good at conducting electricity and heat. – Silver (Ag) and copper (Cu) are some of the most efficient metals and are often used in electronics. • REACTIVITY: – Metals are very reactive. Some more than others, but most form compounds with other elements quite easily. – Sodium (Na) and potassium (K) are some of the most reactive metals. • CHEMICAL: – Metals usually make positive ions when the compounds are dissolved in solution. – Metallic oxides make hydroxides (bases) (OH-) and not acids when in solution. – Sodium chloride (Na. Cl) when dissolved in water breaks apart into sodium (Na+) and chlorine (Cl-). Sodium is the metal. Slide 2

Alkali Metals The far left column is GROUP ONE (Group I). Hydrogen (H) is NOT in the family. The members of the family include. . . Lithium (Li), Sodium (Na), Potassium (K), Rubidium (Rb), Cesium (Cs) and Francium (Fr). They all have one electron in their outer shell. s 1 That's one electron away from being happy (full shells). Alkali Metals are Very REACTIVE. Alkali metals are malleable, ductile, and are good conductors of heat and electricity. The alkali metals are softer than most other metals. Their light weight and physical properties separate them from other metals. Alkali metals can explode if they are exposed to water. Slide 3

Alkaline Earth Metals • Less reactive than Alkali Metals – Have 2 valence electrons and form a +2 charge. – Electron configuration ends with a s 2. • Have higher densities and melting points than Alkali Metals. – Because of their reactivity, the alkaline metals are not found free in nature. – Magnesium and Calcium are most common and most useful. – Beryllium, Strontium, Barium, and Radium are more rare. Slide 4

Transition Metals Transition metals have complex electron configurations. They end with d and f electron orbitals. They have a lot of electrons and distribute them in a variety of ways. Have (+) charges and form cations. Transition Metals are much less reactive than alkali metals. D-block transition metals are very common and useful. F-block transition metals are more rare and less useful. Chromium – very resistant to corrosion, hard, silvery color. Iron – corrodes easily, very abundant and cheap, very strong and durable as steel. Coinage metals – resistant to corrosion and colorful. Used for jewelry and money. Lead – Dense, soft pliable metal, poisonous, very useful in electronics. Lanthanides – little commercial use, expensive, used to color TV screens. Actinides – generally radioactive. Used as nuclear fuel and for nuclear research. Slide 5

Semi-metals • Are the elements found along the stair-step line that distinguishes metals from non-metals. • Have properties of both metals and nonmetals. – Silicon and Germanium, are semi-conductors. – This means that they can carry an electrical charge under special conditions. – This property makes semi-metals useful in computers and calculators Slide 6

Non-metals • Non-metals are not able to conduct electricity or heat very well. • Non-metallic elements are very brittle, and cannot be rolled into wires or pounded into sheets. • The non-metals have no metallic luster, and do not reflect light. • The non-metals exist as gases (such as oxygen) or solids (such as carbon) at room temperature. Slide 7

The Boron Group • Tend to lose three electrons and form positive ions with + 3 charges. – Its electron configuration end with s 2 p 1. • Aluminum is the most important element of the group. – It has a low density, but great strength. – It does not corrode readily in air. • Gallium has a low melting point and is used in fire sprinklers. Slide 8

The Carbon Group • Group includes the element most central to life and the element most central to modern technology. • Carbon is the basis for organic chemistry and forms more compounds than any other element except hydrogen. • The maximum ionic charge is – 4 or +4 making it very versatile. • Tin and lead usually have +2 ionic charges. • More nonmetallic on average than Boron Group elements. • Lower members still distinctly metallic. • Its electronic configuration ends with s 2 p 2. Slide 9

The Nitrogen Group • Nitrogen is a major component of air and is essential to life. – It makes up eighty percent of air on Earth. – It is not very reactive. – It used in fertilizer for plants. • Phosphorus has three allotopes – They are white phosphorus, black phosphorus, and red phosphorus. – Phosphorus is very active in air and burns easily. • Arsenic is poisonous. • Its electronic configuration ends with s 2 p 3. Slide 10

The Oxygen Group • Oxygen, in Group VI of the Periodic Table, makes up nearly half of the Earth's crust by mass. • Oxygen is present in air, and can form a compound with almost every other element. • Sulfur can exist in many allotropic forms at different temperatures. • Its electronic configuration ends with s 2 p 4. Slide 11

Halogens Group VII is the home of the HALOGEN FAMILY. The elements included are. . . Fluorine (F), Chlorine (Cl), Bromine (Br), Iodine (I) and Astatine (At). WHAT MAKES THEM ALIKE? They have seven electrons in their outer shell. They are all just one electron shy of having full shells. Its electron configuration ends with s 2 p 5. Halogen are very reactive with other elements. When a halogen combines with another element the resulting compound is called a HALIDE. One of the best examples of a halide is Sodium chloride (Na. Cl). Slide 12

Noble Gases The far right is also known as GROUP ZERO (Group 0). This family has the happiest elements of all. WHY ARE THEY HAPPY? Happy atoms have full shells. s 2 p 6 All of the inert gases have full outer energy levels. They rarely combine with other elements. That is why they are called inert. WHO'S IN THE FAMILY? Helium (He), Neon (Ne), Argon (Ar), Krypton (Kr), Xenon (Xe) and Radon (Rn). Slide 13