Fundamental Ideas Flashcards
What is an element?
A substance made up of only one type of atom.
It cannot be broken down chemically into any simpler substance
What is an atom?
The smallest part of an element that can still be recognised as that element.
It is made up of protons, neutrons, and electrons
How are elements in the periodic table arranged?
In groups (columns) and in order of their atomic number
What are groups (in the periodic table)?
All the elements in each column going down the periodic table.
They are labelled 1-7 and 0 (sometimes 1-8) and share similar properties
What is the nucleus?
The very small and dense centre of an atom which contains the protons and neutrons.
It has an overall positive charge
What are electrons?
Tiny particles with a negative charge.
The orbit the nucleus of atoms or ions
What happens when elements react?
Their atoms join together with the atoms of other elements to make compounds
What are compounds?
Substances formed when two or more elements react together and become chemically bonded
What are protons?
Tiny, positive particles found inside the nucleus of an atom
What are neutrons?
Tiny, neutral particles found inside the nucleus of an atom
What overall charge does an atom have?
A neutral charge because the number of protons and electrons is the same
What does the number of protons determine?
What element an atom is
What is the atomic number of an element?
The number of protons in an atom
What is the mass number of an element?
The total number of protons plus the total number of neutrons in an atom’s nucleus.
It does not include the total number of electrons because they do not have very much mass
What is an energy level?
An area in an atom, surrounding the nucleus, in which electrons are located
What’s the difference between energy levels and shells?
They’re the same thing
Complete the sentence:
Electrons occupy the…
…lowest possible energy level
Complete the sentecence:
Elements in the same group have the same number of…
…electrons in their highest energy level
Why are the noble gasses unreactive/inert?
Because they have a very stable electron arrgangement.
Their outer shells are full
Draw a diagram to show the electronic configuration of a carbon atom.
Complete the sentence:
The formula for ionic compounds and metallic elements is…
…the simplest possible ratio
For substances made up of molecules, what does its formula show?
The number of atoms in the molecule
E.g. O2 or C2H6
What does the formula of an ionic compound show?
The simplest ratio of ions
How are ionic bonds formed?
- Ionic compounds are formed between when a metal and a non-metal react together
- The metal atoms lose one or more electrons to form a positively charged ions
- The non-metal atoms gain these electrons and form negatively charged ions
- The oppositely charged ions attract strongly to each other, and an ionic bond is formed
When do ionic bonds form?
Between non-metals and metals
How are covalent bonds formed?
Non-metal atoms share the electrons in their outer shells. This forms a covalent bond.
Complete the sentence:
In a chemical reaction, atoms are…
…neither created nor destroyed
‘Atoms are neither created nor destroyed in chemical reactions’.
What can you work out from this?
The number of atoms is the same before and after the reaction.
This means that the mass of the products is equal to that of the reactants
Complete the equation:
A symbol equation should always be…
…balanced!
(Or else you break the universe)
How should you balance chemical equations?
Only by changing the large numbers in from of the formulae for the reactants and products - never the small numbers (subscript)
This is because doing so would change the formula of the reaction (meaning different chemicals would be involved)
Remember: You need the same number of each atom on each side of the reaction!
