P Sci Unit 8 Periodic Table Chapter 5

P. Sci. Unit 8 Periodic Table Chapter 5

Periodic Law • Properties of elements tend to change in a regular pattern when elements are arranged in order of increasing atomic number, or number of protons in their atoms.

Periodic Table The periodic table is arranged in • Periods (horizontal) rows –There are 7 periods • Groups families (vertical) columns –There are 18 columns

Metals • all elements on the left side of the table (except Hydrogen) Non - Metals • all elements on the right side of the table

Hydrogen • Hydrogen (1) – 90% of the atoms in the universe – (diatomic – two atoms of the same element in a covalent bond – H, N, O). Very reactive, both covalent and ionic bonds can form

Metalloids • elements that share both metal and non-metal characteristics – the elements on both sides of the stair-step line except aluminum. • Also called semiconductors

Alkali Metals H hydrogen • (Column 1 except Hydrogen) – the most reactive group – do not occur in nature in their elemental form. Has one electron in its outer energy level • All (including hydrogen) have 1 valence electron.

Alkaline Earth Metals • (Column 2) – also reactive – also do not occur in nature alone (fireworks) • 2 valence electrons. Li Na K Rb

Transition Elements • (Columns 3 – 12) stable metals – occur in natural state. • usually have 2 – 3 valence electrons to give up to form bonds.

Mixed groups • Boron group (13) – mixed with both metals and nonmetals. • 3 valence electrons

Mixed groups cont. • Carbon group (14) – mixed with both metals and non-metals. • 4 valence electrons

Mixed groups cont. • Nitrogen group (15) – mixed – tend to share to form covalent bonds – fertilizers. • 5 valence electrons

Mixed groups cont. • Oxygen group (16) – mixed • 6 Valence electrons

Halogens • (17 – all nonmetal) – very reactive in their element form. If combined with a metal forms salt. Many are diatomic (F, Cl, Br) Br – only nonmetal liquid. • 7 valence electrons

Noble Gases • (18)– Most stable because outer layer is full. No known natural compounds. Helium gas, neon / argon in neon lights, argon / krypton in electric light-bulbs, used to produce lasers • 8 valence electrons (full shell)

Other Groups • Iron Triad – Iron, Cobalt, and Nickel – create steel and other metal mixtures.

Other groups cont. • Coinage group – Copper, Silver, and Gold – stable and malleable and found in nature – used to make coins.

Other groups cont. • Coating metals / Zinc group – Zinc, Cadmium, and Mercury – used to coat or plate other metals – Mercury only liquid metal (cadmium and mercury used in batteries. )

Other groups cont. • Lanthanide series – elements 58 – 71 • Actinide series – elements 90 – 103 • Transuranium – all elements over 92

Allotropes • (recall isotopes) – materials made of the same element that have different molecular structure. Diamonds Graphite

S-113 • What is the periodic Table? • How is it arranged?

S-116 • What subatomic structure is reflected in the periodic table?

Unit 5 The Periodic Table SPS 4 Students will investigate the arrangement of the Periodic Table a. Determine the trends of the following Number of valence electrons Types of ions formed by representative elements Location of metals, nonmetals, and metalloids Phases at room temperature b. Use the Periodic Table to predict the above properties for representative elements

5. 1 Organizing the Elements How did Mendeleev organize the elements in his periodic table? What evidence helped verify the usefulness of Mendeleev’s table?

5. 1 Organizing the Elements How did Mendeleev organize the elements in his periodic table? • 1860 Mendeleev organizes the periodic table – Rows (called periods) by increasing mass • Later by atomic number – Columns (called groups or families) by similar chemical and physical properties – Periodic – means that properties repeat at regular intervals – Only knew 63 elements • He predicted the properties of blanks in his periodic table

5. 1 Organizing the Elements What evidence helped verify the usefulness of Mendeleev’s table? • Mendeleev predicted elements – Eka-aluminum (one below aluminum) • Soft metal with a low melting point and a density of 5. 9 g/cm 3 • 1875 Gallium (Ga) discovered – Soft metal, melting point 29. 7 o. C, density of 5. 91 g/cm 3 • Proved the patterns could be used to predict elements

S-118 • What two characteristics are used to organize the modern periodic table?

5. 2 The Modern Periodic Table How is the modern periodic table organized? What does the atomic mass of an element depend on? What categories are used to classify elements on the periodic table? How do properties vary across a period in the periodic table?

5. 2 The Modern Periodic Table How is the modern periodic table organized? • Periodic Law – Elements are arranged in order of increasing atomic number (protons) – Period – rows on the periodic table • As the row number increases outside electrons are in higher energy levels • First energy level hold 2 – so hydrogen and helium have electrons in first energy level • Second energy level holds 8 – so second row has eight elements

5. 2 The Modern Periodic Table How is the modern periodic table organized? • Periodic Law – Properties of elements repeat in predictable ways and are used to place element in columns – Group – columns • Numbered 1 -18 • Some have names – – 1 2 17 18 alkali metals alkaline earth metals halogens noble gases

5. 2 The Modern Periodic Table What does the atomic mass of an element depend on? • Atomic Mass – Measured in atomic mass units (u) • One twelfth of the mass of Carbon-12 – Average Atomic Mass - calculated using weighted averages • The abundance of an isotope (add up to 100%) • Mass of each different isotope

5. 2 The Modern Periodic Table What categories are used to classify elements on the periodic table? • Elements are classified in three ways – Natural vs Man made • Technetium (Tc) • All elements above 92

5. 2 The Modern Periodic Table What categories are used to classify elements on the periodic table? • Elements are classified in three ways – State of Matter at room temperature • Liquids – Hg, and Br • Gases – Group 18, H, N, O, F, Cl • Solids – the rest of the elements up to 92

5. 2 The Modern Periodic Table What categories are used to classify elements on the periodic table? • Elements are classified in three ways – Metals, Non-Metals, Metalloids • Metals Left of zig-zag line – Transition Metals – group 3 -12 • Non-Metals – right of zig-zag line • Metalloids – touch the zig-zag line, except Aluminum

5. 2 The Modern Periodic Table How do properties vary across a period in the periodic table? • Changes in properties across a periodic table – From left to right • Become less metallic, more nometallic • More likely to gains electrons, less likely to lose them

S-119 • For the element Iron, answer the following questions • 1. metal, nonmetal, metalloid? • 2. state of matter at room temperature? • 3. average atomic mass? • 4. name of group? • 5. period?

5. 3 Representative Groups Why do the elements in a group have similar properties? What are some properties of the A groups in the periodic table?

5. 3 Representative Groups Why do the elements in a group have similar properties? • Valence Electrons – Electrons in the highest occupied energy level – Major factor in chemical reactions – Elements in the same group, have the same valence electrons

5. 3 Representative Groups What are some properties of the A groups? • Alkali Metals – Group one – 1 valence electron – React by losing 1 electron – Gain a positive charge – Highly reactive

5. 3 Representative Groups What are some properties of the A groups? • Alkaline Earth Metals – Group two – 2 valence electrons – React by losing 2 electron – Gain a positive charge – Less reactive

5. 3 Representative Groups What are some properties of the A groups? • Boron Family – Group 13 – 3 valence electrons – React by losing 3 electron – Gain a positive charge

5. 3 Representative Groups What are some properties of the A groups? • Carbon Family – Group 14 – 4 valence electrons – React by sharing electrons

5. 3 Representative Groups What are some properties of the A groups? • Nitrogen Family – Group 15 – 5 valence electrons – React by gaining electrons – Gain negative charge

5. 3 Representative Groups What are some properties of the A groups? • Chalcogens (Oxygen Family) – Group 16 – 6 valence electrons – React by gaining electrons – Gain negative charge – More reactive

5. 3 Representative Groups What are some properties of the A groups? • Halogens – Group 17 – 7 valence electrons – React by gaining electrons – Gain negative charge – Very reactive

5. 3 Representative Groups What are some properties of the A groups? • Noble Gases – Group 18 – 8 valence electrons – Do not react or form compounds

5. 3 Representative Groups What are some properties of the A groups? • Transition Metals (Transition Elements) – Group 3 -12 – 2 valence electrons – Additional electrons are filling lower energy levels – All have similar properties – What we think of as “Metals”

5. 3 Representative Groups What are some properties of the A groups? • Actinide and Lanthenide Series – No group number – 2 valence electrons – Additional electrons are filling lower energy levels – Very few things that we deal with on a regular basis