C1.1 Fundamental Ideas In Chemistry Flashcards
Define element
A substance made up of only one type of atom
How many different elements appear on the periodic table?
100
What do columns on the periodic table contain?
Groups of elements with similar properties
What is a molecule?
More than one atom joined together
Describe the structure of an atom
They have a small central nucleus made up of protons and neutrons around which there are electrons
What is the relative charge and mass of a proton?
- 1
- Positive
What is the relative charge and mass of a neutron?
- 1
- 0 (no charge)
What is the relative charge and mass of an electron ?
- 0.001
- Negative
Why do atoms have no overall charge?
Because the number of electrons is the same as the number of protons.
Define ‘atomic number’
The number of protons/electrons
Define ‘mass number’
The number of protons and neutrons
How are electrons arranged around the nucleus?
Electrons fill up energy levels (or shells) around the nucleus, starting from the lowest energy level (or innermost available shell)
What do all elements in groups in the periodic table have in common?
They have the same number of electrons in their outer shell (or energy level) giving them similar chemical properties)
How do group 1 metals react with water?
They react to form an alkaline solution and hydrogen gas
How do group 1 metals react with oxygen?
They react to form oxides
What are group 0 elements known as?
The noble gases
Why are the nobles gases energetically stable and unreactive?
They have a full outer shell
What are three ways in which atoms react with other atoms to form compounds?
- Losing electrons
- Gaining electrons
- Sharing electrons
What do compounds formed from metals and non-metals consist of?
Ions
What do compounds formed only from non-metals consist of?
Molecules held together by covalent bonds
Describe ionic bonding.
- Its between a metal and non-metal
- The metal loses an electron, becoming a positive ion
- The non-metal gains this electron, becoming a negative ion
- These positive and negative ions are then attracted to each other
Describe covalent bonding
- Its between two non-metals
- Their two outer shells overlap
- They share a pair of electrons
Why is the mass of the products the same as the mass of the reactants?
No atoms are lost or made during a chemical reaction
Define ‘compound’
A substance made from two or more elements that have reacted chemically with each other with different properties from the elements that made it.
