Chemistry Notes: Metal Reactions & Atomic Structure

States of Matter & Atomic Structure

Section 1 – States of Matter

1. Structure of an Atom

• Atoms have a dense, positively charged nucleus consisting of protons and neutrons, around which move negatively charged electrons.

• Protons:

  • Location: Nucleus

  • Relative Charge: 1+

  • Relative Mass: 1

• Neutrons:

  • Location: Nucleus

  • Relative Charge: 0 (neutral)

  • Relative Mass: 1

• Electrons:

  • Location: Electron shells (orbitals) around the nucleus

  • Relative Charge: 1-

  • Relative Mass: Approximately 0 (negligible compared to protons and neutrons)

2. Number of Protons, Electrons, and Neutrons

• Element Identification: An element is identified by its atomic number, which is the number of protons in the nucleus of an atom.

• Neutral Atom: In a neutral atom, the number of protons equals the number of electrons.

• Mass Number: The mass number of an atom is the total number of protons and neutrons in the nucleus.

• Periodic Table Arrangement: The Periodic Table is arranged in order of increasing atomic number.

• Determining Subatomic Particles: From the relationship between atomic number and mass number, you can determine the number of protons, neutrons, and electrons in an atom or monatomic ion.

• Isotopes: Isotopes are atoms of the same element (same number of protons) that have different numbers of neutrons, resulting in different mass numbers.

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3. Ion Formation and Valency

• Valence Electrons: The number of valence electrons (electrons in the outermost shell) for main group elements can be determined using the Periodic Table.

• Electron Shells: Electrons in an atom are located in shells around the nucleus.

• Ion Formation:

  • Positive ions (cations) are formed by the loss of valence electrons.

  • Negative ions (anions) are formed by the gain of valence electrons.

• Charge and Periodic Table Position: The charges of monatomic ions formed by main group elements are related to their position on the Periodic Table. Elements in Group 1 tend to form +1 ions, Group 2 tend to form +2 ions, Group 6 tend to form -2 ions, and Group 7 tend to form -1 ions.

• Stable Electron Configuration: An outer shell electron configuration of a noble gas (Group 8) is considered a stable configuration.

• Electron Configuration: Be able to write the electron configuration of the first twenty elements and their monatomic ions. For example, sodium (Na) has an electron configuration of 2, 8, 1, and its ion (Na+) has a configuration of 2, 8.

• Periodic Table Position: Locate the position of an element in the Periodic Table based on its electron configuration.

• Valence Electrons in Reactions: Valence electrons are involved in electron transfer or sharing to achieve a stable electron arrangement.

Section 2 – Formulas and Equation Balancing

4. Chemical Formulae for Ionic Compounds

• Write the symbols and names of the monatomic ions as shown in the notes.

5. Classifying Substances

• Compounds: Substances that consist of two or more elements chemically combined.

• Elements: Substances that consist of only one type of atom.

• Classification: Classify substances into groups (e.g., elements and compounds, metals and non-metals, ionic, and covalent compounds).

6. Balancing Chemical Equations

• Balance chemical equations to adhere to the Law of Conservation of Mass.

Section 3 – Properties of Metals

7. Physical and Chemical Properties

• Periodic Table and Properties: The main groups of the Periodic Table represent elements with similar chemical properties and the same number of valence electrons.

• Electron Configuration and Arrangement: The arrangement of elements in the Periodic Table is related to their electron configuration.

• Valence Electrons and Properties: The number of valence electrons in the atoms of an element is the most important factor in determining the chemical properties of the element.

8. Physical and Chemical Changes

• Chemical Change:

  • Involves a chemical reaction and the creation of new products.

  • Difficult to reverse.

  • Signs: color change, release of a gas, formation of a solid (precipitate), and production of heat and/or light.

• Physical Change:

  • Does not form new products.

  • Easier to reverse.

  • Examples: change of state (e.g., melting, boiling) and change in the surface area.

9. Properties and Atomic Structure

• Relate the properties of a substance to its atomic structure, especially the number of valence electrons.

10. Reactions of Metals with Air, Water, and Acids

• Acids: Chemicals that dissolve in water to produce hydrogen ions (H+).

• Common Acids (Names and Formulae):

  • Hydrochloric acid: HCl

  • Nitric acid: HNO_3

  • Sulfuric acid: H2SO4

  • Phosphoric acid: H3PO4

  • Ethanoic acid (acetic acid): CH_3COOH

• Write balanced equations for reactions of metals with air (oxygen), water, and acids.

11. Metal Displacement Reactions

• Activity Series/Standard Reduction Table: Use the Activity Series or Standard Reduction Table to predict if acid, air, and water react with metals.

• Reactivity Assumption: Metals above hydrogen in the activity series do not react with water, air, or acid.

• Write balanced equations for metal displacement reactions.

12. Reactivity Order

• Deduce the order of reactivity of some common metals through experimentation.

Science Inquiry Skills/Science as a Human Endeavor

• Describe the observations for reactions involving acids, oxygen, and water with metals.

• Draw inferences from observations of active metal reactions regarding rate of reaction.

• Investigate the chemical activity of metals using metal displacement reactions.

• Develop a suitable method for an investigation by researching established methods.

• Consider ways of safely handling chemicals and carrying out an experiment safely.

• Make qualitative observations of experiment processes.

• Write word and balanced chemical equations to match observations.

• Describe how the model of the atom has changed over time.

• List the evidence that supports Rutherford’s and Bohr’s revised models of the atom.

Vocabulary

• Element, Metal, Atom, Atomic Number, Mass Number, Electron Configuration, Electrically Neutral, Ion, Valency.

• Nucleus, Electron, Proton, Neutron, Period, Group, Electron Shell, Polyatomic, Monoatomic.

• Compound, Ionic Compound, Covalent, Molecule, Lattice, Chemical Property, Reduction.

Common Ions

• Positive Ions (Cations):

  • Aluminium: Al^{3+}

  • Ammonium: NH_4^{+}

  • Barium: Ba^{2+}

  • Calcium: Ca^{2+}

  • Chromium: Cr^{3+}

  • Cobalt: Co^{2+}

  • Copper (I): Cu^{+}

  • Copper (II): Cu^{2+}

  • Hydrogen: H^{+}

  • Iron (II): Fe^{2+}

  • Iron (III): Fe^{3+}

  • Lead: Pb^{2+}

  • Lithium: Li^{+}

  • Magnesium: Mg^{2+}

  • Nickel: Ni^{2+}

  • Potassium: K^{+}

  • Silver: Ag^{+}

  • Sodium: Na^{+}

  • Zinc: Zn^{2+}

• Negative Ions (Anions):

  • Bromide: Br^{-}

  • Carbonate: CO_3^{2-}

  • Chloride: Cl^{-}

  • Ethanoate: CH_3COO^{-}

  • Fluoride: F^{-}

  • Hydrogen carbonate: HCO_3^{-}

  • Hydroxide: OH^{-}

  • Iodide: I^{-}

  • Nitrate: NO_3^{-}

  • Nitride: N^{3-}

  • Oxide: O^{2-}

  • Phosphate: PO_4^{3-}

  • Phosphide: P^{3-}

  • Sulfate: SO_4^{2-}

  • Sulfide: S^{2-}

Tricks for Remembering Ions

1. -ide ending: Usually a negative ion containing one element (e.g., oxide, sulfide, chloride).

2. -ate ending: Usually a negative ion containing oxygen joined to another element (e.g., sulfate, phosphate).

3. -ium ending: Usually a positive ion and usually a metal (e.g., sodium, ammonium).

4. Periodic Table: Can be used to predict charges on ions for Group 1-7 elements.

General Properties of Metals and Non-metals

• Metals:

  1. Lustrous (shiny).

  2. Good conductors of heat and electricity.

  3. High melting and boiling points.

  4. Malleable (bendable/shapable).

  5. Ductile (can be pulled into a wire).

• Non-metals:

  1. Dull appearance (not shiny).

  2. Poor conductors of heat and electricity.

  3. Brittle (snaps/shatters easily).

Atomic Structure Details

• Nucleus: Contains protons (positive charge) and neutrons (neutral charge).

• Electrons: Move rapidly around the nucleus in regions of high probability called electron shells.

• Electron Shells and Periods:

  • The rows (periods) in the periodic table correspond to the number of electron shells.

  • The number of atoms/elements in the first three periods (2, 8, 8) indicates the maximum number of electrons that can occupy the first three electron shells.

• Valence Shell: The outermost electron shell is called the valence shell, and its electrons determine the chemical properties of an atom.

• Groups: The columns (groups) in the periodic table indicate the number of valence electrons.

• Metal vs. Non-metal Valence Shells:

  • Metal atoms tend to have valence shells that are more empty than full.

  • Non-metal atoms tend to have valence shells that are more full than empty.

• Ions are formed when electrons are transferred from the metal atoms to the non-metal atoms.

Writing Ionic Formulae

• Positive ions combine with negative ions.

• The positive ion is written first.

• The overall charge on the compound is always zero.

• Polyatomic ions (radicals) are written in brackets when more than one of these ions is needed.

Covalent Compounds

• Covalent compounds are formed by the joining together of non-metallic elements.

Atoms, Elements, Molecules and Compounds

• Atom: Basic building block of all matter (e.g., gold atom, carbon atom).

• Molecule: Two or more atoms joined together (atoms can be the same or different) (e.g. Water H2O, oxygen gas O2).

• Element: A pure substance made up of only one type of atom (e.g., gold, oxygen gas).

• Compound: A substance made up of two or more different kinds of atoms (e.g., water, carbon dioxide).

Ionic vs. Covalent Compounds

Balancing Chemical Equations

• The number of atoms of each element must be the same on both sides of the equation to obey the Law of Conservation of Mass.

• Hints for balancing:

  1. Balance O last and H second to last.

  2. If you have an odd number of atoms on one side and even number of atoms on the other, then double the odd.

Properties of Metals - Group Trends

• Elements in the same group have similar electron structures and therefore similar properties.

• Physical Properties of Metals:

  1. Malleable (can be flattened into sheets).

  2. Ductile (can be stretched into wires).

  3. Lustrous (shiny).

  4. High melting point.

  5. Conductor of electricity.

  6. Conductor of heat.

Metal Reactions

• Metals react with:

  • Air (oxygen gas).

  • Water.

  • Acid.

  • Other metal ion solutions (displacement reactions).

• Reactivity Series for Metals (from least to most reactive):

Au < Ag < Cu < (H) < Pb < Fe < Zn < Al < Mg < Ca < Na < K

• The most reactive metals (like K) have a weak attraction to electrons and lose them easily, creating the least reactive ions.

• The least reactive metals (like Au) have a strong attraction to electrons and do not lose them easily, creating the most reactive ions.

LEFT OVER RIGHT RULE

Chemicals on the left side of the SRT will gain electrons and those on the right will lose electrons. Find the reduced chemical with your left hand and the oxidized chemical with your right hand. If your left hand is above the right, then you would expect a reaction, but if your right hand is higher or at the same level, then no reaction will occur.

## * Standard Reduction Table
Au3+ + 3 e- → Au
Ag+ + e- → Ag
Cu2+ + 2 e- → Cu
2 H+ + 2 e- → H2
Pb2+ + 2 e- → Pb
Fe2+ + 2 e- → Fe
Zn2+ + 2 e- → Zn
Al3+ + 3 e- → Al
Mg2+ + 2 e- → Mg
Ca2+ + 2 e- → Ca
Na+ + e- → Na
K+ + e- → K