Atomic structure

• all substances are made of tiny particles calle atoms
• protons carry a positive charge
• the nucleus is at the centre of an atom and contains both protons and neutrons
• neutrons have no charge
• electrons carry a negative charge
• electrons orbit around the nucleus
• photon: amount of energy needed to excite an electron to a higher energy lvl
• nucleus of an atom contains protons and neutrons and is the centre of the atom
• Number of protons are equal to the number of electrons
• atomic number is the number of protons in an atom of an element.
• mass number is the total number of protons and neutrons in an atom of an element
• mass number is on the top of the element and the atomic number is on the bottom of the element
• Isotopes an element that has the same number of protons but a different number of nuetrons
• atoms become ions by losing/ gaining electrons