Element Classification
- 1. Unit 4: Periodic Table Classification & Characteristics of Elements “How does an element’s position on the periodic table affect its properties and chemical behavior?” 1
- 2. Element Classifications: Metals, Metalloids & Non-Metals 2
- 3. Element Classifications: Metals • The majority of elements are metals. There are four properties of metals: 1. Metals have luster (are shiny when polished). 2. Metals are excellent conductors (allow heat and electricity to flow through them). 3. Metals are ductile (the metal can be drawn/pulled into wire) and malleable (the metal can be hammered/molded into sheets). 4. Metals like to lose electrons and form positively charged ions (have loosely held valence electrons). 3
- 4. Element Classifications: Metals Alkali Metals – Group 1A elements (except hydrogen): • Very soft and shiny (can be cut easily with a knife). • All have one valence electron (Ve-). • Easily lose their one Ve- to become a positive (1+) ion, resulting in a stable electron configuration. • Extremely reactive, especially with water; never found alone in nature (found in compounds). • Contains the most reactive metals: francium (Fr) and cesium (Cs). 4
- 5. Element Classifications: Metals Alkaline Earth Metals – Group 2A elements: • Found in the Earth’s crust; silver colored, soft metals. • Slightly less reactive than the alkali metals. – have two valence electrons and must lose both to get to a stable electron configuration (resulting in a 2+ ion). • Known for their colors (paint/fireworks). • Usually found as compounds. 5
- 6. Element Classifications: Metals Transition Metals and Inner Transition Metals – Group B elements: • Transition Metals – Hard and tough metals that form colored compounds. – Tend to be unpredictable; most can form variable numbers of bonds (up to three), depending on the element with which it reacts. – Least reactive group of metals, most likely to be found uncombined in nature. – Includes metals used in jewelry and construction. – Called “heavy metals” because of high density. 6
- 8. Element Classifications: Metals Transition Metals and Inner Transition Metals – Group B elements: • Inner Transition Metals – Do not occur in nature (except thorium & uranium). – Highly unstable elements. – Includes Lanthanides (silvery metals) & Actinides (mostly manmade, radioactive metals). 8
- 10. Element Classifications: Metals The Other Metals • Al, Ga, In, Tl & Nh (Boron Group elements) • Sn, Pb, Fl (Carbon Group elements) • Bi, Mc (Nitrogen Group elements) • Lv (Oxygen Group elements) 10
- 11. Element Classifications: Nonmetals • Nonmetals are mostly gases and solids – except Br (l). There are four properties of nonmetals: 1. Nonmetals are dull (they lack luster) 2. Nonmetals are poor conductors (do not allow heat and electricity to flow through them) 3. Nonmetals are brittle and shatter easily (they are not malleable/ductile). 4. Nonmetals like to gain electrons and form negatively charged ions (have tightly held valence electrons). 11
- 12. Element Classifications: Nonmetals Noble Gases – Group 8A elements: •The noble gases are colorless gases that are the most stable/unreactive of all element groups. – Exist as single atoms that have an octet, a full set of eight valence electrons (except He) in their outermost energy level. – EVERYONE WANTS TO BE A NOBLE GAS AND HAVE 8 VALENCES ELECTRONS…8 IS GREAT! – The low reactivity of noble gases leads to some special uses, such as in neon lights. 12
- 14. Element Classifications: Nonmetals Halogens – Group 7A elements: • All have 7 valence electrons. • Like to gain one electron to become a negative (1-) ion, resulting in a stable electron configuration. • Ideally suited to react with the alkali metals (group 1A) • React with most metals to produce a salt. • Contains the most reactive nonmetal, fluorine (F). • Often used as disinfectants and to strengthen teeth. • Most are diatomic (example Cl2). • Poisonous 14
- 15. Element Classifications: Nonmetals The Other Nonmetals • H • C (Carbon Group elements) • N, P (Nitrogen Group elements) • O, S, Se (Oxygen Group elements) 15
- 16. Element Classifications: Metalloids • Metalloids are found on the periodic table between the metals and the nonmetals (border stair-step line). • A metalloid is an element that has some characteristics of both metals and nonmetals. All metalloids are solids at room temperature and can be shiny or dull. • Metalloids are less malleable than metals but not as brittle as nonmetals. • Metalloids tend to be semiconductors of heat and electricity. • Used in computer chips and calculators. 16
- 18. Hydrogen and Helium Hydrogen (H) and helium (He) are special elements. • Hydrogen • Not officially part of a group! • Consists of just one proton and one electron, therefore it behaves unlike any other element (can have the electron traits of two groups: hydrogen is sometimes missing an electron like the members of Group 1A, and sometimes has an extra one as in Group 7A). • Helium • Different from all of the other elements because it is very stable with only two electrons in its outer energy level. Even though it only has two, it is still grouped with the noble gases that have eight valence electrons. 18
Editor's Notes
- #4: Metals like to lose electrons to achieve stability, and form positive ions in the process. Stability is when an atom has a full set of eight valence electrons in their outermost shell (called the octet rule).
- #5: A stable electron configuration means that the element’s outermost energy level is full (has 8 valence electrons Demo of reactivity with water???? Lithium is the least reactive of the alkali metals and trace amounts are found in water, soil and rocks. Lithium is used in all types of batteries, even your cell phone’s! Sodium and Potassium are the most abundant alkali metals (just think of table salt and bananas!) , while cesium and francium are the most reactive.
- #6: Most do not melt in fire, and so were classified as “earths” by the Greeks. Do we want to do the spray bottle demo for colors? It takes more energy to lose two electrons than it takes to lose one. Several of these are important mineral nutrients, such as Mg and Ca…Calcium is found in milk and helps to build dense bones. Have distinguishable flame colors that make fireworks spectacular!
- #7: Uses are wide and varied; they appear in almost every aspect of our day to day life, from electric cabling to decorative door handles to jewelry. Many of these are important for life! Iron is in the center of a hemoglobin molecule (part of our red blood cells). Manganese and Copper are involved in cellular respiration (breathing). These are the metals that are used “as metals”!
- #9: Compounds of lanthanides are used in movie projectors, high-intensity searchlights, lasers, and tinted sunglasses. Americium (an actinide) is used in smoke detectors.
- #11: The rest of the metals are scattered around in several of the other groups, as listed on the slide. The group’s name is given by the first element in the group, as you discovered when completing the ”Periodic Table Basics” Activity. Aluminum is the most abundant metal and the third most abundant element in the earth’s crust. Gallium can melt in your hand and is used in semiconductors and lasers. Lead and Tin are very similar to each other except that lead is toxic. We use tin in the making of our soup cans and lead is used in bullets. Bismuth is commonly found in diarrhea medicines
- #13: We are going to discover that all elements will gain/lose or share electrons until they have 8 in their outermost energy level…in order to be stable like the noble gases. This is called the Octet Rule. Helium is the lightest of the noble gases (only has 2 Ve-)…commonly found in blimps, airships and balloons because it is lighter than air. Neon is used in light displays that are commonly referred to as neon lights...it emits a bright orange light (demo???); others used in neon light include helium (pale yellow) and argon (blue). Argon is the most abundant noble gas in the Earth’s atmosphere...it makes up 1% of Earth’s atmosphere. Argon is used in welding. Argon and krypton are both used to prolong the life of filaments in incandescent lights.
- #14: What do you call a kings fart? A noble gas….
- #15: Recall…Alkali metals want to lose one electron. Halogens want to gain one electron… Fluorine is the most electronegative element on the periodic table, commonly found in toothpaste and drinking water to protect tooth enamel. Chlorine is a deadly gas the reacts with nearly all elements, commonly found in cleaning agents and sanitation. It can also be found in stomach acid. Less of bromine and iodine are produced each year. Iodine is needed to maintain a healthy thyroid and is found in seafood and table salt.
- #16: The rest of the nonmetals are scattered around in several of the other groups, as listed on the slide. The group’s name is given by the first element in the group, as you discovered when completing the ”Periodic Table Basics” Activity. Carbon is one of the most important elements on Earth. The branch of chemistry that studies compounds containing carbon is called organic chemistry. The majority of all living organisms are carbon based. Carbon is the bases of fuels such as coal and oil and a key component of steel. And diamonds come from carbon!
- #17: Metalloids are the elements that border the stair-step line on the periodic table. They have properties of both metals and nonmetals.
- #18: What do you call a clown who's in jail? A silicon.
- #19: Hydrogen is the most common element in the universe! It is estimated that 3 out of every 4 atoms in the universe are hydrogen. How many energy levels does helium have? 1 How many electrons will fill the first energy level? 2 How many electrons does helium have in that energy level? 2 So…it as a full outer energy level…