Ionic Compounds

Reactivity Unit Overview

• Models and patterns explain how systems show the relationships between the physical and chemical properties of elements.
• Global Context: Scientific and Technical Innovation
• ATL skills include: Self management, thinking, and research.

Atomic Structure

• Matter is composed of atoms.
• The evolution of the atomic model can be described.
• Parts of an atom include: location and charge.
• Relative masses of protons, neutrons, and electrons.
• Sizes of atoms, protons, neutrons, and electrons measured using correct units of measurement and appropriate scientific notation.
• Electrons are arranged inside atoms.

The Periodic Table

• The basic structure consists of 8 columns known as groups.
• The periods are the 7 rows
• The center consists of transition metals
• Potassium (K) and Flourine (F) are elements on the table

Group 1 Alkali Metals

• Group 1 metals react with water.
• Group 1 metals are stored under oil to keep them from reacting with oxygen in the air.
• Reactivity increases down the group as atoms become larger and the outer electron becomes further from the nucleus.
• Lithium, sodium, and potassium all float on water due to their low density.
• They react with water to form alkaline compounds which is why they are called alkali metals.

Electron Configuration

Steps to draw Bohr Diagrams:

• Find the element on the periodic table.
• Determine the number of electrons from the atomic number.
• This is number of electrons to draw
• Find period (row) element is in.
• Elements in the 1st period have one shell.
• Elements in the 2nd period have two shells and so on.
• Draw a nucleus with element symbol inside.
• Draw the shells around the nucleus.
• Add the electrons; Carbon has 6 electrons
• The first shell can only hold 2 electrons
• Since need to add 4 draw these in the 2nd shell.
• Add one at a time starting on the right side and going counter clockwise.
• Check the work and have the total number of electrons; Carbon total is 6 electrons.
• There can only be two electrons that can fit within the first shell.
• The 2nd shell and upwards can hold up to 8 electrons.

Reaction Success Criteria

• All students should be able to observe the reaction of the metals.
• Most students will be able to order the reactivity.
• Some students will be able to explain how the different reactions contribute to the order of the reactivity of group 1 elements.

How Metals React with Water

• Most metals usually react slowly with water or not at all.
• Metal + water yields metal hydroxide + hydrogen.
• Calcium reacts with water to produce calcium hydroxide and hydrogen.

Reactivity Series

• Know the different properties of metals and nonmetals.
• Explain how the properties of metals are linked to their uses.
• Use information about the reactions of metals to devise a reactivity series of metals
• Make predictions about the reactions of metals using the Reactivity Series.
• Describe the corrosion of metals, and how to prevent it.
• Metals that tarnish react with oxygen to form metal oxides in an oxidation reaction: metal + oxygen yields metal oxide.
• Understand why different metals have to be extracted from their ores in different ways.

Extraction

• Reactive metals that have combined with other elements in rocks are extracted.
• Use a displacement reaction.
• A displacement reaction has a more reactive metal displacing a less reactive metal out of a solution.
• A balanced symbol equation reflects the reactions of the metal and oxygen..

Earth's Crust Elements

• Metals are a relatively small proportion of the Earth's crust
• Metals are normally found in rocks as ores
• Oxygen: 46%
• Silicon: 28%
• Aluminium: 8%
• Iron: 5%
• Calcium: 4%
• Sodium: 3%
• Magnesium: 2%
• Potassium: 2%
• Titanium: 0.5%
• Hydrogen: 0.5%
• All other elements: 1%

The Reactivity Series Ranking

• Very Reactive: requires extraction by electrolysis.
  • Potassium (K)
  • Sodium (Na)
  • Calcium (Ca)
  • Magnesium (Mg)
  • Aluminium (AI)
• Fairly Reactive
  • Carbon (C): Reduced with Carbon
  • Zinc (Zn)
  • Iron (Fe)
  • Lead (Pb)
  • Copper (Cu)
• Not at all Reactive: don't need extracting.
  • Gold (Au)
  • Platinum (Pt)

Native Metals

• Metals found as an element in nature.
• Metal ore: A naturally-occurring compound found in the Earth's crust, which needs to be chemically separated before the metal can be used as an element.
• Many metal ores are oxides, so to obtain the metal, the oxygen must be removed.

Metal Ores

• Rocks that contain metals are called ores.
• Extracting metal steps from an ore:
  • The ore is mined.
  • The ore is separated from its impurities.
  • The ore is converted to a metal.
  • The metal formed is then purified.
• Recycling metals:
  • Saves money.
  • Reserves of metal last longer.
  • Avoids waste and pollution.
  • Reduces the environmental effects of mining.
  • Saves energy.

Ions and Ionic Bonding, Ion Description

• Group 1 elements form 1+ ions
• Group 2 elements form 2+ ions
• Group 3 elements form 3+ ions
• Group 5 elements form 3- ions
• Group 6 elements form 2- ions
• Group 7 elements form 1- ions

Ionic Bonding

• Form ions with two different elements.
• Show how electrons transfer from one to the other.
• Atoms can bond together based upon the transfer electrons.

Ionic Compound Recap

• Ions form when elements try to get full outer shells
• Ions will gain or lose electrons, dependent on which takes the least amount of energy
• If an ion gains negative electrons, it becomes negative.
• If an ion loses negative electrons, it becomes positive.

Forming Ions

• If it loses 1 electron, it gets a + charge.
• If it loses 2 electrons, it gets a +2 charge.
• If it loses 3 electrons, it gets a +3 charge.
• If it gains 1 electron, it gets a - charge.
• If it gains 2 electrons, it gets a 2- charge.
• If it gains 3 electrons, it gets a 3- charge.

Ionic Compounds

• Sodium Cations are positively charged and lose electrons.
• Anions are negatively charged and gain electrons
• Cations are electrostatically attracted to the oppositely charged anions when forming an ionic compound to transfer of electrons.
• Cations and anions combine and form ionic compounds
• Strong bonds hold the ionic compounds together
• Positive and negative charges attract

Ionic Formula Writing, Steps:

• Write the cation and its charge first
• Write and anion and its charge
• Draw an arrow
• Show the product
• If the two ions have the same charge, then charges are dropped.
• If the charges are different, you swap and drop them below; no number listed if only one atom.

Formula Naming

• The cation is always named first and then the anion.
• The cation is named as the element name (without any change).
• The anion is named as the first part of the element name, with changing the suffix into -ide.

Covalent Bonding

• Nonmetal atoms share electrons
• Simple molecules can form or giant covalent structures can form
• Single covalent bonds is a shared pair of electrons
• Bonds in most polyatomics and diatomics consist of covalent bonds
• Compounds contain more than one covalent bond