Lesson 6 — Activity 2: Understanding Chemical Compounds
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Lesson 6 — Activity 2:
Understanding Chemical Compounds
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In the previous activity, you looked at how to name compounds using their elements. In this activity, you will look closer at why some chemical compounds include numbers as well as the symbols for the elements.
As the periodic table was developed to help scientists organize and describe elements, scientists have also developed a standard procedure for naming compounds. Although we know many chemical compounds by everyday names, the periodic table allows scientists to identify various compounds by their chemical formulas. These formulas use the symbols in the periodic table for the elements that are part of the compound and numbers to show how many of each element form the molecules that make up the compound.
Let's
take a look at how to name molecules with two elements (called binary
compounds). The name of a compound with two elements has two words.
To
get the first word, we use the name of the first element, or the leftmost element in the formula. To get the second word, we use the name of
the second element and change the suffix to "ide" at the end of the
word.
Some examples of adding the "ide":
O = oxygen = oxideCl = chlorine = chlorideBr = bromine = bromideF = fluorine = fluoride
Let's take a look at how to name molecules with two elements (called binary compounds). The name of a compound with two elements has two words.
To
get the first word, we use the name of the first element, or the leftmost element in the formula. To get the second word, we use the name of
the second element and change the suffix to "ide" at the end of the
word.
Some examples of adding the "ide":
O = oxygen = oxideCl = chlorine = chlorideBr = bromine = bromideF = fluorine = fluoride
Examples of binary compounds (two elements):
NaCl = sodium (Na) chlorine (Cl) = sodium chlorideMgS = magnesium (Mg) sulfur (S) = magnesium sulfide
Examples of binary compounds (two elements):
NaCl = sodium (Na) chlorine (Cl) = sodium chlorideMgS = magnesium (Mg) sulfur (S) = magnesium sulfide
What
happens if there is more than one atom? Remember, a number after the element
shows how many atoms of that particular element are in one molecule of
the compound. In cases where there is more than one atom (for example
there are two oxygen atoms in CO2), you add a prefix to the start of the
element based on the number of atoms. Here is a list of the prefixes
used:
What
happens if there is more than one atom? Remember, a number after the element
shows how many atoms of that particular element are in one molecule of
the compound. In cases where there is more than one atom (for example
there are two oxygen atoms in CO2), you add a prefix to the start of the
element based on the number of atoms. Here is a list of the prefixes
used:
Take a look at the compounds listed below. See if you can figure out which elements (and how many of each element) make up each compound.
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