Science Chemistry Facts Flashcards
(19 cards)
Atom
The smallest part of an element that is still the element
Compound
Two or more elements chemically bonded together. The proportion of each element is fixed, e.g H2O
Element
Contains only one type of atom, e.g oxygen only contains oxygen atoms
Mixture
Different elements and/or compounds together but not chemically bonded. The proportions are not fixed
Products
A substance made as a result of a chemical reaction
Reactants
A substance we start with before a chemical reaction takes place
Symbol equation
A way of describing what happens in a chemical reaction by showing the formulae of all reactants and the products they form e.g 2Na+CI2 –> 2NaCI
Word equation
A way of describing what happens in a chemical reaction by showing the names of all reactants and the products they form e.g Sodium+ chlorine –> sodium chloride
Law of conservation of mass
The total mass of the products formed in a reaction is equal to the total mass of the reactants
State symbols
Abbreviations used in symbol equations to show if reactants and products are solid liquid or gas or dissolved in water
Protons
A tiny positive particle found in the nucleus of an atom
Neutrons
A tiny negative particle found in the nucleus of an atom
Electrons
A tiny negative particle found orbiting the nucleus of an atom electron shells
Mass number
The number of protons plus neutrons in the nucleus of an atom
Isotope
Atoms that have the same number of protons but different number of neutrons
Electronic structure
A set of numbers (or diagram) to show the arrangement of electrons in their shells e.g Na (281)
Group
Columns in the periodic table are called groups. Elements in the same group of the periodic table have similar chemical properties
Period
Rows in the periodic table are called periods, elements in the same period have their outer shell electrons in the same shell
Displacement reaction
A reaction which is more reactive element takes place of a less reactive element in one of its compounds
