Question | Answer |
What sub-particles make up an atom? | Protons, Neutrons and Electrons |
What is nomenclature? | The chemical symbol that is used to represent an element. |
What is the Atomic number? | The Atomic number is the smaller number and indicates the number of protons or electrons |
What is the Mass number? | The Mass number is the number of protons and neutrons |
What is the Nucleus? | The centre of the atom. It contains all the weight of the atom. Protons and Neutrons are in the nucleus. |
What are the electron shells and what do they do? | The electrons move around the nucleus of the atom. They are very light and do not contribute to the mass of the atom. |
What are the 3 subatomic charges? | Protons: positive charge
Neutrons: neutral charge
Electrons: negative charge |
How many electrons can fit in each shell? | K:2, L:8, M:18, N:32 |
What is a Valence electron? | The number of electrons in the outmost shell |
What are Isotopes? | Isotopes are atoms of the same elements that differ in the number of neutrons in the nucleus. (all isotopes have the same atomic number) |
True or false are all isotopes stable? | False |
What is a stable isotopes? | A stable isotope is one that does not emit radiation, or, if it does its half-life is too long to have been measured |
What is a chemical reaction? | A chemical change has taken place when a new substance is formed |
What are the signs of a chemical change? | -Smell of a new substance
-Permanent colour change
- Gas is given off
-Change in temperature indicating energy is produced or absorbed.
-Precipitate or solid is formed (mixing two substances together)
-One metal deposits on another |
What are the signs of a physical change? | -Changes shape
-Breaks into smaller pieces
-Dissolves
-Mixes with another substance |
Reactants and Products | Reactants are the substances present at the start of the chemical reaction and products are the new substances that are formed |
How do chemical reactions change? | |
What is an endothermic reaction? | An endothermic reaction is a reaction that absorbs heat, taking it from the surroundings and making them feel colder. Endothermic reactions need energy to proceed and they get their energy from what is around them |
What is an Exothermic reaction? | While endothermic reactions absorb energy, exothermic reactions release energy.During the reaction, energy is released into the surroundings, usually as heat and or light. |