Key Concepts In Chemistry Flashcards
John Dalton atom?1803
Three-part atomic theory, all substances are made of atoms that can’t be split or destroyed. Atoms of each element are identical. Particles of other elements are different. Atoms join with other atoms to make new substances. Much was correct but later proven incorrect.
J.J Thomson atom?1897
Used a cathode ray to disprove Dalton, atoms can be divided into smaller parts. Thomson knew some particles must have a negative charge. He proposed plum pudding model.
Rutherford atom?(1909)
Rutherford developed a model suggesting most of the atoms mass is found in a centre nucleus and that electrons travel in paths around the nucleus
Proton charge and mass?
+1,1
Neutron charge and mass?
0,1
Electron charge and mass?
-1,nearly 0
Mass/neucleon number?
Number of protons+neutrons
Atomic/proton number?
Number of protons
Why do atoms have same amount of electrons and protons?
They’re neutral, so negative and positive charge has to equal out
Isotopes?
Atoms of the same element with different number of neutrons
Mendeleev’s periodic table?
In order of atomic mass or weight. Left space for events he felt hadn’t been discovered yet. Noticed each group had similar properties. Lack of knowledge on isotopes can explain why the mass/weight order was sometimes wrong because when you take isotopes into account thus can change
Current periodic table?
Arranged in order of increasing atomic number , in rows called periods. Elements with similar properties are placed in the same columns called groups.
What does the group tell you about electron configuration?
The group tells you how many electrons it has in their outer shell. Eg, group 1 will have 1 electron on outer shell. The period tells you how many shells it has. Maximum for each shell 2:8:8
Ionic bonding?
Metals and non-metals bond. Metals give an electron so become positively charged. Non-metals gain that electron and become negatively charged
What is an ion?
A positively or negatively charged atom of an element
Ide at the end of compounds?
Compound contains two elements, one being non metal
Compounds ending in ate?
Compound contains at least 3 elects, one being oxygen
Explain the structure of an ionic compound as a lattice structure?
Giant structure of ions= ionic compound
Held together by strong electrostatic forces of attraction with oppositely charged ions
Forces act in all directions
Lattice has a regular arrangement of ions
Covalent bonding?
Bonding between non-metals
They share pairs of electrons, creating covalent bonds which are very strong
Examples of giant covalent structures?
Diamond, silicon dioxide
Law of conservation of mass?
No atoms are lost or made during a chemical reaction, so the mass of products= mass of reactants
How to find moles?
Moles= mass/molar mass
Making soluble salts:MASH
Metal, acid, salt, hydrogen
Making soluble salts: BASHO
Base, acid, salt, water
Making soluble salts:CASHOCO
Metal Carbonate, acid, salt, water, carbon dioxide
Distillation separates?
Two liquids
Chromatography separates?
Separate soluble substances based on solubility
Soluble in water?
Common sodium, potassium and ammonium salts, all nitrates, most chlorides, most sulphates, sodium potassium and ammonium carbonates, sodium potassium and ammonium hydroxides
Insoluble in water?
Silver and lead chlorides, lead, baranium and calcium carbonates, most carbonates, most hydroxides
Why is graphite softer than diamond?
Graphite has a localised electron in between the layers, this means the layers can slide over one another, making graphite softer. Diamond is strong because it has 4 bonds for each atom.
