Periodic Table Atomic Structure Do not write what

Periodic Table & Atomic Structure Do not write what is in blue What is in red is important Physical Science January 2015

Periodic Table History • Dimitri Mendeleev: Russian, developed the 1 st periodic table, which was arranged by atomic mass. • Henry Mosley: English, developed the modern periodic table, which is arranged by increasing atomic number & properties.

Basic Arrangement of the Periodic Table • ↓vertical columns: called groups or families. Every member of has the same number of valence electrons. • Valence electrons: electrons in the outermost energy level of an atom (determines properties and how compounds are formed). As you move from left to right across the periodic table you increase valence electrons by 1 (excluding the transition metals) until you reach 8 in the noble gases. Elements with the same number of valence electrons have similar properties (due to reactivity) • → Horizontal rows: called periods. Each row has the same number of energy levels. • Metals are located to the left of the staircase • Non-metals are located to the right of the staircase. • Metalloids follow (create) the staircase.

Basic Arrangement- Fill this Information out on your Table

Periodic Properties • Properties of (most) Metals – solid at room temperature – shiny (metallic luster)—good reflectors – good conductors of heat & electricity – Flexible( Malleable: able to be hammered into thin sheets – Ductile: able to be drawn into wire) • Properties of (most) Non-metals – Gases or brittle solids at room temperature – Dull (earthy luster) – Do NOT conduct heat or electricity well – Brittle • Properties of Metalloids or Semiconductors: Have properties of both metals and nonmetals. – They are actually non-metals with some properties of metals such as being able to conduct heat and electricity under certain conditions. They are often used in computers and calculators. • Elements may be: – Reactive: will react with other elements to form compounds – Inert: will NOT react with other elements

Exceptions to the Rules • Mercury, Hg is the only metal that is a liquid at room temperature. • Bromine, Br is the only non -metal that is a liquid at room temperature. • Hydrogen, H is the only non-metal that is on the left side of the chart.

Element Groups • Hydrogen • Falls in line with group 1 because it only has one valence electron --although it is not a metal. • When it gains an electron, it behaves as a non-metal • When it loses an electron, it behaves as a metal • http: //www. periodicvideos. com/videos/001. htm (03: 30)

Element Groups • • Group 1: Alkali Metals One electron in outer energy level Only found in nature as a compound Most reactive group • • https: //www. youtube. com/watch? v=uixx. Jt. JPVXk Alkali Metals https: //www. youtube. com/watch? v=m 55 kgy. Ap. Yr. Y (start at 1 min)

Element Groups • • Group 2: Alkali Earth Metals Two electrons in outer energy level Only found in nature as compounds Very reactive • Colored fireworks https: //www. youtube. com/watch? v=Ebk. Lp 3 -o 78 E

Element Groups • Groups 3 -12: Transition Metals: They are less reactive than metals from groups 1 & 2.

Element Groups • Groups 13 -16: Mixed Groups • The groups are “mixed” because they contain metals, non-metals, and metalloids. Each group is referred to by the top elements name. https: //www. youtube. com/watch? v=mzah. TEBa. F 8 (diamonds aren’t forever)

Element Groups • • Group 17: Halogens All are non-metals The word halogen means “salt former”. Each element has 7 electrons in its outer energy level.

Element Groups • Group 18: Noble Gases • All are non-metals and gases • They have 8 electrons in their outer energy levels so they are already stable and do not need to combine. • They do NOT form compounds naturally…. they are inert. • http: //www. youtube. com/watch? v=QLrofyj 6 a 2 s Noble Gases • • https: //www. youtube. com/watch? v=ozkyh 515 p. Jc (Nova)

What is an Atom? • Atom: basic unit of matter. All atoms have two regions Nucleus (+ charge) • Electron cloud (- charge) http: //www. youtube. com/watch? v=bw 5 TE 5 o 7 Jt. E (In Search of Giants)

Three Sub-Atomic Particles Symbol used Location Proton Neutron Electron 1 amu + or p+ 0 or Nucleus 1 amu Around the nucleus Negligible (So small it can be ignored for our calculations. ) n 0 - or e- Mass http: //www. youtube. com/watch? v=xq. NSQ 3 OQMGI (nova animation of atomic models)

Atomic Arrangement

Finding Atomic Mass • Atomic Mass Unit (amu): a quantity equal to onetwelfth the mass of a Carbon -12 atom. • The # of P+ determines the type of atom. • The number of p+ = number of e • To determine mass number from the chart, round the average atomic mass to the nearest whole number. • To determine # of Neutrons, subtract the atomic number from the mass number.

Atomic Number ( # of P+ or # of e-) 4 Beryllium Be 9. 0122 Element Name Chemical Symbol Average Atomic Mass (# of P+ + # of N 0) Complete the chart for Beryllium Element Name Number of Protons Number of Electrons Atomic Number Chemical Symbol Average Atomic Mass Number of Neutrons Mass # - Atomic #

Atomic Number ( # of P+ or # of e-) 4 Beryllium Be 9. 0122 Element Name Chemical Symbol Average Atomic Mass (# of P+ + # of N 0) Complete the chart for Beryllium Element Name Number of Protons Number of Electrons Atomic Number Chemical Symbol Average Atomic Mass Number of Neutrons Beryllium 4 4 4 Be 9. 0122 amu 9 5

Complete Carbon Element Name Number of Protons Number of Electrons Atomic Number Chemical Symbol Average Atomic Mass Number of Neutrons 6 Carbon C C 12. 011

Complete Carbon Element Name Number of Protons Number of Electrons Atomic Number Chemical Symbol Average Atomic Mass Number of Neutrons Carbon 6 6 6 C 12. 011 12 6 6 Carbon C 12. 011

Fill out for the Missing Element Depending on your Birthday. Compete the Chart • • • January- Lithium February- Na March- 39 amu April- Atomic # 7 May- Chlorine June- Atomic # 10 July- 14 amu August- Atomic # 13 September- S October- Phosphorus November- 40 amu December- F Element Name Number of Protons Number of Electrons Atomic Number Chemical Symbol Average Atomic Mass Number of Neutrons

How are Electrons Arranged? • The electron cloud is located around the nucleus of the atom. • The electron cloud is arranged into energy levels (shells), each of these levels is filled with orbitals, and electrons are most likely found in these areas within the electron cloud. The lowest energy level is closest to the nucleus.

How are Electrons Arranged? • As you move away from the nucleus, the energy levels are capable of holding more and more electrons. Energy level Maximum # of electrons 1 2 2 8 3 18 4 32

Bohr Models • A Bohr model of an atom depicts the number of electrons within each energy level. • The energy levels are represented by circular orbits and the electrons are dots on the orbits. • You must be able to recognize Bohr models of elements 1 -20.

Now you Try! • On your blank periodic table draw models for elements #1 -18.

Recall • Valence electon- number of electrons in the outermost shell • Elements with the same number of electrons in their outer shell have similar properties – Ex/ groups 1 elements all react similar because they all have one valence electrons • The groups determine the valence electrons • Groups 1 and 7 have the most reactive elements because they want to loose or gain an electron rapidly • Groups 8 is stable because elements in this group have a full outer shell- they do not want to gain or lose any electrons

Neutral or Charged Ion? • • • Ionization: When atoms gain or lose electrons In a neutral atom, # of protons = # of electrons. So the overall charge is zero. Ion: a charged atom (# of P+ is different from # of e-) Losing e- = + charge(cation) (cation- think of the t as a + or ca+ion, or cats have paws- form a pawwssitive charge) Gaining e- = - charge (anion) (anion= a negative ion- forms a negative charge) https: //www. youtube. com/watch? v=WFFtdx. NYd. Es Metals usually lose e- and form cations (+) Non-metals usually gain e- and form anions (-)

• Gaining e- makes more neg (-), this forms an Anion • Losing e- makes more pos (+), this forms a Cation • Mg+2 Lost two electrons • O-2 Gained two electrons

Lewis Dot Diagrams • Used to represent valence e-. • Electrons can be paired or unpaired in the Lewis Dot Structure. • Generally, the electrons that are available for combining into a compound are unpaired. • Draw the Lewis dot structures for: • Carbon Oxygen Chlorine

Lewis Dot Diagrams • Complete the worksheet in your own notes!! • Write the – Lewis dot structure – Element name – Atomic # – Atomic mass

Isotopes • The number of neutrons in the nucleus can vary! • These variations are called ISOTOPES. • Isotope: atoms of the same element with a different number of neutrons. (Different mass)

How to Calculate Isotopes • Isotopes are symbolized as follows: Mass Number Carbon -12 Atomic Number • To calculate the # of neutrons in the isotope, • subtract the atomic number from mass number. • The above isotope has 6 neutrons (12 – 6 = 6).