Week 4

Class 1: Metals and Non-metals

Before we learn about how elements combine to form complex molecules, we are going to review a general classification of elements: metals and non-metals. 

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Even if this is the first time someone studies the topic, everybody has a general idea of what a metal is and how it looks. That's why we will start with a little game to try to guess if some elements are metals or non-metals.

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Then, we will go to the library and will have a station rotation activity in which you will rotate through different activities:

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The purpose of this class is to learn the difference between an element and a compound and the way in which simple compounds are named.

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The class will start with an explanation of the rules to name compounds:

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Then, we will watch a video that helps us clarify the questions we may have about the topic:

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Finally, we will solve the following classwork:

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1) Describe two ways in which sodium chloride is different from chlorine

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2) Which two elements are combined to make these compounds?:

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a) Sodium chloride

b) Hydrogen sulfide

c) Magnesium oxide

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3) A student wrote this name for a compound made of calcium and sulfur: sulfur calcium. What is wrong with this name? Write the correct name for the compound

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4) Which three elements are combined in:

a) calcium nitrate

b) magnesium carbonate

c) lithium sulfate

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During this class, we will practice

naming compounds with 2 or 3

elements and we will also practice

how to write the chemical formula

of simple compounds.

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Every compound has a chemical name and a chemical formula. The formula contains the symbols of the elements that are bonded together in the compound. Next to the symbol (in the right part), we can find a little number that indicates the number of atoms of that element found in one molecule of the compound. If there is no number. that means there is just one atom of that element.

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Examples:

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CO2 has one atom of carbon bonded to two atoms of oxygen

H2S has two hydrogen atoms bonded to one sulfur atom

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Hydroxides

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There is one more kind of compound that you need to know about. These are the hydroxides. These are compounds that contain one element plus hydrogen and oxygen (OH). These substances are strong alkalis, or the opposite of acids because they have a high pH. Its name and formula its always the name of the other elements + hydroxide:

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Sodium hydroxide       =         NaOH

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Let's practice the names and formulas of different compounds by solving this activity:

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1) Name the following compounds according to the rules studied in class:

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KBr: _____________________________________________________

CaO: ____________________________________________________

LiI: ______________________________________________________

NaBr: ____________________________________________________

MgO: _____________________________________________________

KOH: _____________________________________________________

CaCO3: __________________________________________________

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2) Write the formula for the following compounds:

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Rubidium hydroxide

Carbon monoxide

Nitrogen monoxide

Nitrogen dioxide

Dinitrogen trioxide

Aluminium hydroxide

Sulfur hexafluoride

Boron phosphide

Diphosphorus pentoxide

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3) Complete the table using the name, formula, the number of atoms and elements present in the compound, and the total number of atoms the compound has:

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