Chemistry Flashcards
What are atoms?
Atoms are small particles of matter, that are made up of electrons, protons and neutrons
What is matter?
Matter is everything around us that has a mass and occupies space.
What is an element?
An element is a substance made up of just one type of atom so it cannot split up into simpler substances.
In chemistry each element is given a ? for it’s long name?
chemical symbol
What are the four major elements in the human body?
carbon, hydrogen, oxygen and nitrogen account for 96% of the human body.
Protons and neutrons together form what?
Nucleus of an atom.
Protons have a ? charge and a mass of approx.?
positive charge and mass of approx. 1.
Electrons are ? charged and have ? mass.
Negatively charged and have no mass at all.
Electrons move in groups around the nucleus known as?
electron shells
The number assigned to each element on the periodic table correlates to what?
The number of protons and electrons in each element.
How do you work out the number of neutrons?
Mass number - atomic number
What are isotopes?
Atoms of the same element which have different numbers of neutrons in the nucleus?
What is a stable element? Give an example.
It will have an equal number of electrons and protons giving an overall neutral charge. Hydrogen - one proton, one electron, no neutrons.
What do isotopes affect?
They change the mass of the element
Hydrogen only has one electron in it’s outer shell also known as? and what does this mean?
the valence electron. It will often go looking for another atom that needs one electron to fit it’s shell. This means H easily reacts with other atoms.
Elements which do not easily react because their outer shells are filled with perfect numbers are called?
Inert
If an atom gives up or gains electrons to stabalise it’s outer shell, it becomes what?
An ion.
Ionisation is the process of what?
giving or gaining electrons
Donating electrons to another element creates what type of charge?
Positive charge
Gaining electrons from another element creates what type of charge?
Negative charge
What is oxidation?
The removal of electrons from an atom or molecule.
Oxidation ? the potential energy of the compound.
Decreases
Generally, most oxidation occurs with the removal of?
Hydrogen
When something is reduced it ? electrons, resulting with the increase of energy in that molecule.
Gains electrons
When oxidation and reduction reactions happen together, it is known as ?
Redox reactions