C1-Atomic Structure And C2-Periodic Table Flashcards
What is an atom
the smallest part of an element that can still be recognised as that element
What is an element?
A substance which is made up one atom and cannot be broken down.
What are compounds
Compounds are two or more elements chemically combined in fixed proportions and can be represented by formulae using symbols of the atoms.
How can compounds be seperated
Chemical reactions
What is a mixture
A mixtures consists of two or more elements or compounds not chemically combined together.The chemical properties of each substance in the mixture are unchanged.
The first development of the atom
John dalton-start of 19th century-atoms were described as solid spheres
2nd part of history of atoms
JJ thomson-1897-plum pudding model-the atom is a ball of charge with electrons scattered.
3rd advancement of history of atoms
Ernest rutherford-1909-nuclear model-alpha scattering experiment-mass concentrated at the centre;the nucleus is charged.Most of the mass is in the nucleus.Most atoms are empty space.
4th of history of atoms
Niels Bohr-1911-planetary model,electrons are in shells orbiting the nucleus.Specific distance from nucleus
Last of history of atoms
James chadwick-1940-discovered that there are nuetrons in the nucleus
How the ernest rutherford experiment worked
A beam of alpha paeticles projected at a gold foil,the gole foil surrounded by flourescent screen to detect alpha particles.Most of the alpha particles passed through but some were deflected by the centres of the metal atoms and a tiny bumber were repelled.Suggesting the nucleur model(the nucleus in middle with electrons in around)
What is the atomic number
The number at the bottom which shows the number of protons and electrons.
Mass number
The sum of the protons and nuetrons in an atom
Isotopes
Atoms of the same elements with different numbers of nuetrons
What isrelative atomic mass
An average value that takes account of the abundance of the isotopes of the element.
How to calculate relative atomic mass
(Isotope 1 times abundance) +(isotope 2 times abundance) divided by 100
What is the periodic table
an arrangement of elements in the order of their atomic numbers, forming groups and periods
How was john new lands periodic table like
Ordered his table in order of atomic weight,Worked in law of octaves but this broke down
How did dmitri mandeleevs periodic table work
It was ordered in order of atomic mass but not always strictly in some places he changed the order based on atomic weights.Left gaps for elements that were not discovered
What are metals
Elements that react to form positive ions-found at left of periodic table
What are non metals
Elements that do not form positive ions-found at right and top of periodic table
Characteristics of alkali metals
They react with oxygen to create oxide,they all readt with chlorine to form a white percipitate,the reactivity increases going down the group.There melting and boiling point decreases going down the group
How does lithium react with oxygen
Burns with a strongly red tinged flame and produces a white solid
How does lithium react with water
Fizzes,disappears gradually
How does lithium react with chlorine and give equation
Burns to give white solid
Lithium+chlorine=lithium chloride
How does sodium react with oxygen
Strong orange flame and produces white solid
How does sodium react with water
Fizz,melts into a ball and disappears quickly
How does sodium react with chlorine
Burns with a bright yellow flame,cloud of white powder and settle on the sides of the container
How does potassium react with oxygen
Large pieces produce lilac flame,smaller ones make solid immediately
How does potassium react with water
Ignites with sparks and disappeaes
How dows potassium react with chlorine
Burns to give white solid
Characteristics of noble gases
All full electrons in outer shell,are uncreative,stable,the boiling points increase going down the group
Characteristic of halogens
Similar reactions,react with metals to form ionic compounds (shared pair of electrons),going down the group the mass increases,melting point and boiling increase,but the reactivity goes down.
Why does the reactivity go down for halogens going down the group?
Halogens react by gaining an electeon and as the number of shells of electrons increases going down the element with the least amount of shells is more reactive as there is less shielding compared to other elements.
Characteristic of transition metals
Harder and stronger,higher melting points,less reactive and dont react as vigorously with oxygen or water,form different colour solutions,good conductor of electricity,can become any positive ion like 2+ or 3+
Defintion of transition metal
The collection of metallic elements in the middle of the periodic table
What is an ion
An atom or molecule with an electric charge due to the gain or loss of electrons
How has Advances in Experimental Technology
Improved experimental methods revealed new information about atomic structure.
How has the discovery of subatomic particles led to change in the model of the atom
Discovery of particles like electrons, protons, and neutrons showed that atoms had internal structure.
How has the Limitations of Previous Models led to change into the model of the atom.
Each model had flaws that couldn’t explain certain atomic behaviors.
What are subatomic particles
Nuetrons,electrons,protons
Mass of protons and nuetrons
1.67 x10^-27
Mass of electron
9.11x10^-31
What are valence electrons
All the electrons in the outer shells
What is a group in the periodic table
A group of elements with similar reactivitys and chemical properties
What is a period in the periodic table
A horizontal line of elements with atomic numbers going up each time,increasing valence electrons and changing properties
What is atomic weight
Atomic weight is basically atomic mass is a measure of the average mass of an atom of an element.
How was john daltons periodic table like
1808-John dalton
Elements arranged by atomic weight
Only 20 elements listed
(And not all were actually elements
Advantages and disadvantages of john daltons periodic table
Advantages:early attempt to organise the elements
Disadvantages:Symbols difficult to use and identify
Most elements not yet been discovered.
What does periodic mean
Regurley occuring
explain how and why the ordering of the elements has changed over time.
The way elements are ordered has changed because scientists learned more about atoms and found new elements. Early methods grouped elements by their properties but didn’t work for all of them. Mendeleev created a better table based on atomic weight and predicted missing elements. Later, Moseley showed that atomic number (the number of protons) is more important for ordering elements. This led to the modern periodic table, which is arranged by atomic number and helps us understand how elements behave.
explain the significance of chemical symbols used in formulae and equations.
Easy Identification: Quickly identifies different elements.
Composition: Shows which elements and proportions make up a compound.
Bonds and Reactions: Represents how elements bond and react in equations.
Universal Language: Standardized symbols allow global understanding.
explain why mass is conserved in
a chemical reaction.
Mass is conserved in a chemical reaction because atoms are simply rearranged, not created or destroyed. In any reaction, the total number of each type of atom in the reactants equals the total number in the products.
justify in detail how mass may
appear to change in a chemical reaction.
practical observations may lead to apparent changes due to gas exchange, measurement errors, physical state changes.
Difference between compound and a mixture
A compound is 2 elements which have been chemically bonded together and this cannot be reversed wheras a mixture is 2 elements that have been mised together and this can be reversed
experimental data to explain the classification of a substance as a compound or a mixture.
If your data shows a single, sharp melting or boiling point, it’s likely a compound.
If your data shows a range of temperatures, it’s likely a mixture.
explain how the chemical properties of a mixture relate to the chemical it is made from.
The chemical properties of a mixture are determined by the substances it is made from, but the substances do not chemically combine,just physically , so each retains its own properties.
Why the model of the atom has changed over time
Subatomic particles were discovered,better experimental techniques,better understanding of atomic behaviours
Subatomic particles charges
Protons=+1
Nuetrons=0
Electrons=-1
explain how evidence from scattering experiments changed the model of the atom.
the scattering experiments revealed that atoms are mostly empty space with a central nucleus
explain why we can be confident that there are no missing elements in the first 10 elements of the periodic table.
We can be confident that the first 10 elements are correct as they all go up in electron structures,have different chemical reactivitys compared to eachother and a complete atomic number sequence
Why does chlorine not have a whole mass number
Abundance of chlorine 35 and 37 gives answer of 35.5
Describe how the electronic structure of metals and non metals is different
We can see for non metals they most of the time require the extra electron so the elements nearest the top of the table are higher reactive compared to lower wheras metals lose there electron to non metals to form a positive ion and there reactivity increases towards the lower of the group
explain in terms of electronic structure how the elements are arranged in the periodic table
We can see as the table progresses the different elements have different electronic structures as there atomic numbers and subatomic particles change depending where they are.There valence electrons also change depending if they are a metal which means they lose electrons becoming a positive ionor non metal which means they gain electron becoming negative jon
First three elements in group 1
Lithium,sodium,pottasium
What is a monotimic molecule
Consisting of one atom
What is a diatomic molecules
Diatomic molecules are molecules that contain only two atoms bonded to one another.
Describe how you can show that hydrogen and metal hydroxides are made when Group 1 metals react with water.
Adding a few drops of an indicator will cause the water to turn purple or pink , showing that the solution is alkaline.
And lastly in chemical reaction equations we can see that hydrogen and hydroxide is formed.
Justify how Group 1 metals are stored and the safety precautions used when dealing with them
Group 1 metals are stored in oil so they do not oxidise and react with the oxygen.When dealing with group 1 metals you need to wear gloves and goggles and when reacting them you need to react them behind a screen
First four elements in Group 7
Flourine,chlorine,bromine,iodine
Difference between ionic bond and compound
Ionic bond is force that hold them together and ionic compound is everything.
What is an ionic bond
strong electrostatic. force of attraction between these oppositely charged ions
What is an ionic compound
Ionic compounds are formed when two atoms, one of which is a metal, interact and exchange electrons.
What are ionic compounds held by
Ionic compounds are held by strong electrostatic forces of attraction by there oppositly charge ionic bonding.Between a metal and a non metal
What is a halogen displacement reaction?
A halogen displacement reaction occurs when a more reactive halogen displaces a less reactive halogen from a compound
How does chlorine displace pottasium bromide(equation)
chlorine + potassium bromide → potassium chloride + bromine
Cl,(aq) + 2KBr(aq). → 2KCI(aq) + Br, (aq)
Obviously fluorine, the most reactive of the halogens, will displace all of the others. However, it reacts so violently with water that you cannot carry out reactions in aqueous solutions.
What is an aqueous solution
aqueous solution” is a solution in which water is the solvent, such as salt dissolved in water
Why do halogens have similar reactions
They all have 7 electrons in the outer shell in which they have to gain 1 to then become a negative ion.They do this with ionic bonds with metals or covalent bonds with non metals
Why is mercury not a normal transition metal
Has low melting point
Compounds of transition metals
Compounds of transition elements are coloured (as opposed to the mainly white compounds of the alkali metals). The colours of many minerals, rocks and gemstones are due to transition element ions. The reddish-brown colour in a rock is often due to iron(III) ions, Fe’. The blue colour of sapphires and the green of emeralds are both due to transition element ions in the structures of their crystals
Common compounds of transition metals
copper(II) sulfate is blue (due to its Cu+2 ions)
• nickel(Il) carbonate is pale green (due to its Ni+2ions)
chromium (III) oxide is dark green (due to its Cr’+3 ions)
• manganese(II) chloride is pale pink (due to its Mn?+2 ions)
justify the use of a transition metal or its compound in terms of its chemical properties.-
they are not reactive with water and oxygen so they can be used for structures due to less rust, and can also be used for catalysts
Relative mass of protons and nuetrons and electrons
Protons and nuetrons=1
Electrons=0
Three differences of plum pudding model and nuclear model
Plum pudding is a ball of positive charge
Mass in nucleur model is concentrated wheras plum pudding its spread out.
Nucleur model has positive charge concentrated at nucleus wheras plum pudding its spread out
Electrons inside for plum pudding wheras nucleur has them outside
Similarites of plum pudding and nucleur
Both have electrons,both have positive nucleus,no nuetrons
Differences in physical changes of transition and group 1
Transition is harder,denser,high melting,group 1 has low melting points,soft,
Differences in chemical changes of transition to group 1
Transition has low reactivity,used as catalysts,ions eith different charges wheras group 1 is very reactive,not used as catalysts and can only for a +1 ion
Polyatomic ion for ammonium
Nh4 +
Polyatomic ions for carbonate
Co3 2-
Key formulas
Nh3=ammonia
Ch4=methane
Nacl=sodium chloride (salt)
Co2=carbon dioxide
H2O=water
SiO2=sand
Hydrochloric acid
Hcl (aq)
Nitric
HNO3 (aq) [H] + [NO3]- nitrate
Sulfuric
H2SO4 (aq) 2[H]+ [SO4]2- sulfate
Phosphiric
H3PO4 3[H]+ [PO4]3- phospate
What is the electronic structure
a set of numbers to show the arrangement of electrons in their shells
Radium of atom
0.1nm (1x10-10m
Radium of nucleus of atom
(1x10-14m)
