Ch 2 - Elements + The Periodic Table

Chemical Symbols Always start with: Can be ___ or _____ letters

Periodic Table:color code your table!

Metals, Non-metals, Metalloids Fill in the graphic organizer to record the basic properties of groupings on the periodic table!

READING the TABLE Atomic # Tells us: Atomic Mass Therefore, The # of neutrons =

Practice:

Do the Atomic Structure Worksheet Name of Element Symbol of Element Atomic Number Atomic Mass Number of Protons Number of Electrons Number of Neutrons K 35 Al Li 12 8 Ni 10 18 Gold 11 Pb

Potassium K 19 39 20 Bromine Br 35 80 45 Aluminum Al 13 27 14 Lithium Name of Element Symbol Atomic Number Atomic Mass Number of Protons Number of Electron Number of Neutrons Potassium K 19 39 20 Bromine Br 35 80 45 Aluminum Al 13 27 14 Lithium Li 3 7 4 Magnesium Mg 12 24 Oxygen O 8 16 Nickel Ni 28 59 31 Neon Ne 10 Argon Ar 18 40 22 Gold Au 79 197 118 Sodium Na 11 23 Lead Pb 82 207 125

Chemical Formulas tell you which elements are present in a compound, and their amount Each new element is denoted by a CAPITAL LETTER. NaCl = sodium and chlorine MgBr =magnesium and bromine

The subscript (the small number slightly below the line) tells you how many atoms are present – that number only applies to the element at the immediate left of the number.

Ex. H2O = 2 hydrogen atoms 1 oxygen atom CaCl2 = 1 calcium atom 2 chlorine atoms

Coefficients are large numbers written in front of the compound symbol Coefficients are large numbers written in front of the compound symbol. This tells you how many molecules of that compound you have.

Ex. 5NaNO3 = 5 Na atoms 5 N atoms 15 O atoms 4NH4ClO3 = 4 N 16H 4 Cl 12 O

Brackets around a complex ion, with a number to the immediate right of the brackets, tells you how many of that complex ions you have in the compound. That number applies to all elements inside the bracket.

Ex. (NH4)2SO4 = 2N, 8H, 1S, 4O Ex. 4Ca3(PO4)2 = 4[3Ca 2P, 8O)] = 12 Ca, 8P, 32O

Mg(NO3)2 = 3Ba3(PO4)2 = 1 magnesium atom 2 nitrogen atoms 6 oxygen atoms Mg(NO3)2 = 3Ba3(PO4)2 = 9 Barium atoms 6 potassium atoms 24 oxygen atoms

Do the Reading Chemical Formula Worksheet Number of Different Types of Atoms Names of Each atom present Number of each type of atom Total Number of Atoms present Number of molecules of this compound Ex. 2NaCl 2 Sodium Chlorine 2 sodium 2chlorine 4 3N2O3 2KHCO3 5FeSO3 C6H12O6 3K2Cr2O7 CH3COOH Mg(OH)2 3 Al(OH)3 4CuClO3

Potassium Hydrogen Carbon Oxygen 2 Potassium 2 Hydrogen Chemical Formula Number of Different Types of Atoms Names of Each atom present Number of each type of atom Total Number of Atoms present Number of molecules of this compound Ex. 2NaCl 2 Sodium Chlorine 2 sodium 2chlorine 4 3N2O3 Nitrogen Oxygen 6 N 9O 15 3 2KHCO3 Potassium Hydrogen Carbon Oxygen 2 Potassium 2 Hydrogen 2 Carbon 6 Oxygen 12 5FeSO3 Iron Sulphur Oxygen 5 Iron 5 Sulphur 15 Oxygen 25 5 C6H12O6 Carbon Hydrogen Oxygen 6 Carbon 12 Hydrogen 6 Oxide 24 1

Potassium Chromium Oxygen 6 Potassium 6 Chromium 21 Oxygen 33 Chemical Formula Number of Different Types of Atoms Names of Each atom present Number of each type of atom Total Number of Atoms present Number of molecules of this compound 3K2Cr2O7 3 Potassium Chromium Oxygen 6 Potassium 6 Chromium 21 Oxygen 33 CH3COOH Carbon Hydrogen Oxygen 2 Carbon 4 Hydrogen 2 Oxygen 8 1 Mg(OH)2 Magnesium Oxygen Hydrogen 1 Magnesium 2 Hydrogen 2 Oxygen 5 3 Al(OH)3 Aluminum Oxygen Hydrogen 3 Aluminum 9 Oxygen 9 Hydrogen 21 4CuClO3 Copper Chloride Oxygen 4 Copper 4 Chloride 12 Oxygen 20 4

Study for Quiz! Atomic Structure worksheet Reading Chemical Formula Worksheet Models of Molecules

Drawing Bohr Diagrams of Atoms The nucleus contains all the protons and neutrons. Consequently, all the mass is concentrated in the nucleus. The electrons are arranged in specific ORBITALS around the nucleus.

Orbital Limits There is a specific limit to how many electrons an orbital (or shell) can hold. Within the orbitals, the electrons like to spread themselves out.

Why Spread out? electrons carry negative charges negative charges repel

Electrons fill the orbitals in the following pattern: Orbital: 1st 2nd 3rd 4th 2e- 8e- 8e- 18e- Which of these diagrams is incorrect? What elements are A,B,C,and D

Once an orbital is full, the electrons will start filling the next orbital. The innermost orbital (#1) gets filled first.

Example: Hydrogen Atomic # = ______ Atomic Mass = ______ # protons = ______ # neutrons = ______ # electrons = ______ 1 1 1 1

Example Lithium Atomic # = ______ Atomic Mass = ______ # protons = ______ # neutrons = ______ # electrons = ______ 3 7 3 4 3

Example: Chlorine Atomic # = ______ Atomic Mass = ______ 17 Atomic # = ______ Atomic Mass = ______ # protons = ______ # neutrons = ______ # electrons = ______ Now do the worksheet: “Models of the elements” 36 17 19 17

The Valence Shell Definitions: 1) Valence Shell: the outermost orbital (or shell) 2) Valence Electrons: _electrons in the outside shell The Valence Shell

The Valence Electrons are involved in forming bonds with other atoms The Valence Electrons are involved in forming bonds with other atoms. The inner electrons and nucleus are not involved in bonding.

Atoms can: - _gain valence electrons - _lose valence electrons - _share valence electrons

Example: Oxygen Atomic # = _8____ Mass = ___16___ #p = _8___ #e = _8___ #n = _8___

Combining Capacity: The number of electrons that an atom must gain or lose to have a full valence shell. Full for 1st shell = _2e-___ Full for 2nd shell = _8e-___ Full for 3rd shell = _8e-___

Will an Atom Gain or Lose Electrons? Valence electrons Gain/Lose? greater than 4 gain less than 4 lose equal to 4 gain or lose

exception: HYDROGEN This element is unique because it has the ability to either gain or lose one electron to “fill” its orbitals.

combining capacity? _3-_ Charge ? __3- Examples: Nitrogen atomic # = _____ mass = _____ #p = _7____ #n = _7____ #e = _7____ # valence e = _5____ Will this atom gain or lose? __gain_ How many ? ___3____ What is its combining capacity? _3-_ Charge ? __3- 7 14

When nitrogen is charged it is called _nitride

Example 2: Neon atomic # = _10____ mass = ___20__ #p = __10___ #n = __10___ #e = __10___ # valence e = __8___ Will this atom gain or lose? __neither___ How many ? ___0____ What is its combining capacity? _0_____ Charge ? __0____ Atoms with C.C. =_0=_INERT (NOBLE)_ that is , they will not blow up! (or react at all!)

Now go back and answer the questions on the Bohr diagram worksheets! Charge: Atoms are neutral if #p+ = # e- If atoms gain or lose electrons they become _charged = IONS!_. Now go back and answer the questions on the Bohr diagram worksheets!

When naming NON-METAL ions, _change__ the name _ending_ to “_ide___” e.g. _oxygen___ = __oxide_______ __fluorine___ = _fluoride

Non-metals form _negative ions. (_#e- > #p+) Metals form _positive_ ions. (_#e- < #p+)

Study for Bohr Diagrams Quiz!