Elements, Compounds, Mixtures Flashcards
What is an atom, element, compound and a mixture?
Atom - the smallest part of an element that can exist. Everything is made of atoms
Element - a substance made of only one type of atom
Compound - two or more different elements chemically bonded together
Mixture - elements and/or compounds mixed but NOT joined together.
The periodic table
Identify correct symbol of element?
H = Hydrogen Cu = copper Zn = zinc Ag = silver K = potassium Na = sodium He = helium etc…
Writing element symbols?
The Capital letter at front and lowercase at back/ if one letter, then just capital letter
Like this: Not like this
H / He. HE or he or hE
Particle diagram for elements, compounds and mixtures + examples. Test yourself before looking!
What is chemical bond?
A chemical bond joins atoms together
Group on the periodic table?
A vertical column on the periodic table e.g. group 1 contains the elements lithium, sodium, potassium, caesium and francium.
Periods on the periodic table?
A horizontal row on the periodic table e.g period 1, period 2 etc…
What is monatomic?
A substance made from atoms that exist on their own (individual atoms)
What is diatomic?
A molecule made from two atoms joined together (paired atoms) - O2 , H2
Solids, liquids and gases
Solids are ternary arranged in a pattern and are more compact/ stronger bond between atoms
Liquids are arranged randomly but still have a good bond between each other/ generally can flow
Gases are arranged really randomly and have a weak bond between each other as they are far away from each other/ easy flow and fly
Deducing number of atoms of a compound from its chemical formula.
Subscript - the small number under a element in a compound formula —> H2O = 2 H, 1 O
If there is no subscript under a number, we just say it’s only has 1 atom.
The number outside a parenthesis tells us to multiply everything inside the bracket
Ca(OH2)2 = 1 Ca, 2 O and 4 H. Total = 6
The number infront of a chemical formula (co-effecient number) tells us to multiply everything in the chemical formula (if there is brackets in the question, you do the brackets first then the co-effecient number)
2Ca(O2H3)2 = 2 Ca, 8 O, 12 H. Total = 22 (REMEBER BRACKETS FIRST)
1) H2O3 = 2 H, 3O. Total = 5
2) K(O4H)3 = 1 K, 12 O, 3 H. Total = 16
3)4Ca2(N2O3)2 = 8 Ca, 16 N, 24 O. Total = 48
Name the process used to split up the elements in a compound.
Electrolysis. Using electrical energy to split up a compound into elements.
Electro = electricity, lysis = split up.
Explain why a mixture can be separated by physical means (e.g filteration) but a compound cannot?
Components of a mixture can be separated by physical methods because particles remain separate without chemical reactions between them as they mixed but NOT joined.
However, a compound is a pure substance composed of two or more different atoms chemically bonded to one another. That means that it can not be separated into its constituents by mechanical or physical means and only can be destroyed by chemical means.
