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Chemistry
flash cards for chemistry
Question | Answer |
---|---|
What are the three sub-particles of an atom? | Protons, Neutrons and Electrons. |
What is nomenclature? | The chemical symbol that is used to represent the element. |
What is an atomic number? | The atomic number is the smaller number and indicates the number of protons (or electrons). |
What is a mass number? | The mass number is the number of protons and neutrons. |
What is the nulceus? | The nucleus is the centre on an atom. It contains all the weight (mass) of the atom. Protons and neurons are in the nucleus. |
What are electron shells and what do they do? | The electrons move around the nucleus of the atom. The are very light and do not contribute to the mass of the atom. The shell’s are named K, L, M and N. |
What are the subatomic charges? | Protons have a positive charge, neutrons are neutral (no charge) and electrons have a negative charge. |
What is the srtucture of an atom? | The protons and neutrons are found in the nucleus and the elecrtons are found in the electron shells. |
How many electrons can fit in each shell? | K: 2, L: 8, M: 18, N: 32. |
What is electron configuration? | The electron configuration shows the way in which the shells have been filled. It is written as K, L, M, N (where each letter is the number of electrons in the atoms shells) |
What are valance electrons? | Valance electrons are the number of electrons in the outermost shell. |
How is electron configuration written? | For example: if there are 13 electrons in total, 2,8,3. |
What are isotopes? | Isotopes are atoms of the same element that differ in the number of neutrons in the nucleus. All isotopes have the same atomic number. |
Are all isotopes stable? | No, not all isotopes are stable. Stable describes a nucleus that does not change spntaneously. |
What is a chemical reaction? | A chemical change has taken place and a new substance is formed. |
What are the signs of a chemical reaction? | Smell of a new substance, permanent colour change, gas is given off, change in temperature indicating energy is produced or absorbed, percipicate or solid is formed (mixing two substances together, one metal deposits on another. |
What are the signs of a physical reaction? | changes shape, breaks into smaller pieces, dissolves, mixes with another substance. |
What are reactants and products? | Reactants are substances that are present at the start of a chemical reaciton and products are the new substances formed. |
How can the substances change in a chemical reaction? | Particles combine to make a new substance, particles break apart, particles combinations 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. The products of these reactions have more energy than the reactants. |
What is an Exothermic reaction? | While Endothermic reactions absorb energy, Exothermic reactions release energy. The reactants have more energy that the products. |