The Periodic Table Flashcards
(36 cards)
What are all substances composed of?
All substances are either elements or composed of elements.
What is an element?
An element is a pure substance that consists of only one type of atom.
Can an element be broken down?
An element cannot be broken down by chemical methods.
What is assigned to each element?
A symbol consisting of one or two letters is assigned to each element.
How are element symbols formatted?
All symbols begin with a capital letter and if there is another letter, it is written in lower case, e.g. H for hydrogen, C for carbon, Ca for calcium, and Cl for chlorine.
What forms when atoms of different elements combine?
Atoms of different elements combine in a fixed ratio to form compounds.
What is a compound?
A compound is a pure substance that consists of two or more different atoms, e.g. water has two hydrogen atoms and one oxygen atom.
Can a compound be broken down?
A compound can be broken down into elements by reactions such as electrolysis.
What does a chemical formula show?
A compound has a chemical formula that shows what elements are present and how many atoms of each element are in one molecule, for example, the chemical formula H2O.
What charge do protons have?
Protons have a positive charge.
What is the charge of neutrons?
Neutrons are neutral (have no charge).
What is contained in the nucleus of an atom?
The nucleus contains protons and neutrons, called nucleons.
What are the three main subatomic particles?
The atoms of an element consist of protons, neutrons, and electrons.
Where are electrons found?
Electrons are found in the space around the nucleus.
What is the charge of an atom?
Atoms generally have no charge: the total number of protons is equal to the total number of electrons.
How are elements classified?
Elements can be classified into metals, metalloids (semi-metals), and nonmetals.
What is the chemical formula for water?
The chemical formula for water is H2O.
What is the chemical formula for table salt?
The chemical formula for table salt is NaCl.
What is the arrangement of elements in the Periodic Table?
The elements are arranged in order of increasing atomic numbers, which is the number of protons.
What does the dividing line on the Periodic Table indicate?
The dividing line (stepped line or zigzag line) separates the metals and nonmetals from one another.
Where are the metals located on the Periodic Table?
To the left of the dividing line are the metals.
What are metalloids?
Some of the elements on either side of the dividing line are metalloids or semi-metals.
Where are the nonmetals located on the Periodic Table?
To the right of the dividing line are the nonmetals.
What percentage of all elements are metals?
An average of 75% of all the elements are metals.
