Lesson plan (English)
Topic: Structure of salts and nomenclature
Target group
Elementary school student (grades 7. and 8.)
Core curriculum
Elementary school. Chemistry.
VII. Salts. Student:
2) creates and writes the total formula of salts: chloride, sulphides, nitrates, sulphates, sulphates, carbonates, phosphates (orthophosphates); creates salt names based on formulas; create and write the total salt formulas based on names.
General aim of education
The student creates and writes salt formulas and names based on formulas
Key competences
communication in foreign languages;
digital competence;
learning to learn.
Criteria for success
The student will learn:
describe the construction of salt;
create salt names.
Methods/techniques
activating
discussion.
expository
talk.
exposing
film.
programmed
with computer;
with e‑textbook.
practical
exercices concerned.
Forms of work
individual activity;
activity in pairs;
activity in groups;
collective activity.
Teaching aids
e‑textbook;
notebook and crayons/felt‑tip pens;
interactive whiteboard, tablets/computers.
Lesson plan overview
Introduction
The teacher hands out Methodology Guide or green, yellow and red sheets of paper to the students to be used during the work based on a traffic light technique. He presents the aims of the lesson in the student's language on a multimedia presentation and discusses the criteria of success (aims of the lesson and success criteria can be send to students via e‑mail or posted on Facebook, so that students will be able to manage their portfolio).
The teacher together with the students determines the topic – based on the previously presented lesson aims – and then writes it on the interactive whiteboard/blackboard. Students write the topic in the notebook.
Realization
The teacher writes on the blackboard next to each other the formulas of sodium and chloride anion. It indicates the sodium chloride formula based on the valence of the metal and the acid residue, explaining at the same time the principles of determining the total salt formula. The same action is shown on the example of aluminum sulphide, copper(II) nitrate, magnesium phosphate.
The students consolidate the acquired information, discussing it with their nearest neighbors („tell your neighbor” method).
The teacher explains the rules for creating salt names derived from anaerobic and aerobic acids, based on examples of salts used in the third point of this scenario.
Next, the teacher writes down some examples of total salt formulas on the board and asks the students to fix their names and write them down in the notebooks. The readers read them out loud. The lecturer refers students to the abstract in order to analyze the tables „First names of salts derived from various acids” and „Sample salt formulas and names”.
The teacher asks students (working in pairs) to do selected interactive exercises in abstract.
Summary
The teacher asks the students to finish the following sentences:
Today I learned ...
I understood that …
It surprised me …
I found out ...
The teacher can use the interactive whiteboard in the abstract or instruct students to work with it
Homework
Listen to the abstract recording at home. Pay attention to pronunciation, accent and intonation. Learn to pronounce the words learned during the lesson.
Make at home a note from the lesson using the sketchnoting method.
The following terms and recordings will be used during this lesson
Terms
sole – związki chemiczne o budowie jonowej składające się głównie z kationów metali i anionów reszty kwasowej
Texts and recordings
Structure of salts and nomenclature
Salt is the common name of cooking salt, whose main ingredient is sodium chloride. However, this is not the only compound that can be determined by this name. It also applies to other substances, e.g. potassium chloride, copper mono‑sulphide. Salts are a huge number of compounds with some characteristic features.
Are all salts salty?
Not every salt is salty. There are tasteless salts (e.g. calcium carbonate). There are also salts that are described in the literature as spicy or refreshing (potassium nitrate). Magnesium sulphate due to its taste has been called bitter salt.
Salts are built of metal cations (or ammonium cation as following ) and anions of acid residue. General formula is:
where:
– symbol of metal, which cation is in salt,
– symbol of acid residue, which anion creates salt,
– stoichiometric indices determined on the basis of the valence of the metal and the acid residue.
The valency of the acid residue is equal to the absolute value of its ion charge, e.g. the valence of the sulphate ion, , equals 2.
Salts are made of ions, so they belong to the group of ionic compounds. As solids they form crystals with an ordered structure.
The salt names consist of two parts: the first refers to the type of the acid residue, the second refers to the metal. The part derived from the name of the acid residue has an ending the tip - ate (-ite) (in the case of salts of oxoacids) or - ide (for salts of hydracids). For example, salts derived from sulphuric or sulphurous acid will be called sulphates/sulphites, and hydrogen sulphide derivatives – sulphides. Sometimes the names of salts include the valence of the non‑metal, which is part of the acid residue, and metal.
First part is the name of the metal. If it can have different valency it can be sometimes added to the name. So, iron trichloride (iron(III) chloride), , is other substance than iron dichloride (iron(II) chloride), .
Salts are a group of ionic chemical compounds that consist of metal cations (or an ammonium cation of the formula ) and anions of the acid residue.
The name of the salt consists of two parts: the name of the acid residue and the name of the metal. When the salt comes from the oxyacid, the ending is - ate/ite, and when from hydracid – ending is - ide.
Sometimes in the salt name the valence of the metal is included, which can take on a different numerical value.