atoms Flashcards
(22 cards)
What is an atom?
An atom is a basic particle.
What is the difference between an atom and a molecule?
A molecule is made up from a number of atoms. For example a water molecule is made from 2 hydrogen atoms and 1 oxygen atom (H2O)
Are all atoms identical?
Atoms of one element are identical to each other. They have the same number of protons and the same number of electrons. But atoms from different elements are not the same as each other.
What is at the centre of an atom.
The centre of an atom is called its nucleus. Consists of protons and neutrons.
What do we call the positive particles inside an atom?
Protons
What are electrons? Say at least 2 things.
Electrons are very small particles which are in the outside parts of the atom. They have a negative charge.
What is an element?
An element is a substance which contains only one sort of atom.
Roughly how many elements are there?
About 100
What is the difference between an element and a compound.
An element has only one kind of atom.
A compound is made up from different elements.
Water is a compound.
Most substances are compounds.
True or False?
True.
Most substances are made by combining a number of elements.
Water is an element
True or False?
False. Water is a compound made from water molecules (Hydrogen and Oxygen)
Describe the three subatomic particles which make up an atom
proton - positive
neutron - neutral
electron - negative
A whole atom has neutral charge.
True or false
True .
- the + and - charges of protons and electrons balance each other out.
If atoms come from one element, they will have the same number of protons.
True or False?
True
What does the atomic number of an atom tell you?
It tells you the number of protons in that atom
Explain the ‘mass number’ of an atom.
Protons and neutrons each have a mass of ‘1’.
The overall mass of the atom is calculated from the number of protons plus neutrons.
(An electron is so tiny, its mass is not included.)
The elements in the periodic table are arranged according to the number of protons in each element (atomic number)
True or False?
True. The atomic number increases from left to right in the periodic table.
How many electrons can the first electron shell hold?
2
How many electrons does the second electron shell hold when it is complete?
8
If an atom looses an electron it becomes negatively charged. True or False?
False. If it looses an electron if means there are more protons than electrons, and overall it is positive, It is called a positive ion. Metal atoms can lose electrons and become positive ions.
A negative ion is formed when an atom gains an extra electron.
True or false
True. It is called a negative ion.
non- metal atoms can gain electrons.
What is a covalent bond?
This a way that two elements bond (join together) by sharing electrons.
