Elements, compounds and mixtures Flashcards
What are elements?
Elements are substances that cannot be broken down into any other substance. They are made up of only one type of atom.
What is the periodic table?
The periodic table is a list of all the elements known in order of their atomic number
Of what are H, O, Cl and Na examples?
Chemical symbols (hydrogen, oxygen, chlorine and sodium)
Elements are made up of one or more….
Elements are made up of one or more atoms. There is only ever one type of atom in an element.
How do the properties of a single atom differ from the properties of a group of atoms in an element?
Groups of the same atom give an element its properties but a single atom does not have the same properties as its element.
What is the most common element on earth?
The most common element in the Earth is oxygen, accounting for 46% of the atoms.
What is the most common element in the human body?
Oxygen is the most common element in the human body, comprising approximately 65.0% of body mass. Most of the oxygen present is found in the form of water.
What is the main element in air?
Around 78% of air is Nitrogen.
Name three precious metallic elements.
Gold (Au), platinum (Pt), silver (Ag).
What is a compound?
A compound is a substance made up of atoms of two or more different elements. The atoms are strongly joined (bonded) together.
What are the chemical symbols for the elements carbon, chlorine, gold and iron?
C (carbon)
Cl (chlorine)
Au (gold)
Fe (iron)
What is an atom?
An atom is the smallest part of an element that can exist. A single atom does not have the properties of the element, which is made up of many atoms. An atom is not a solid, liquid or gas - there have to be many atoms to take on the properties of those states.
What are properties of gold?
Gold is yellow and shiny, it is a solid at room temperature.
Water exists as molecules. The molecules are made up of atoms of two elements, meaning that water is a compound.
How do the properties of water differ from the properties of the elements hydrogen and oxygen, from which it is made?
Water is a liquid at room temperature.
Hydrogen is a gas at room temperature and is highly explosive.
Oxygen is a gas at room temperature, it is colourless and odourless.
Which has a higher boiling point, water or hydrogen?
Molecules in liquids are held together by forces. Those forces between molecules are stronger in liquid water than in liquid hydrogen. Therefore, it takes more energy to separate water molecules from each other than to separate hydrogen molecules from each other. So, water has a higher boiling point than hydrogen.
