Atomic Structure and the Periodic Table Flashcards

Question

What is the formula for Ammonia?

Answer 1

Na₂CO₃

Answer 2

* With a word equation * With a symbol equation

Answer 3

* Reactants are the molecules and ions and elements on t**he left hand side of the arrow** in a chemical reaction equation because they react with each other

Answer 4

* Products are the molucules and ions **on the right hand side of the arrow** in a chemical reaction equation because they have been produced from the reactants

Answer 5

* Mixtures are formed of compounds and elements that have no chemical bond between them e.g. flour and sugar (before baking!)

Answer 6

* Filtration * Crystallisation * Simple Distillation * Fractional distillation * Chromatography

Answer 7

* The properties of a mixture are just the properties of the separate parts. * The chemical properties of a substance aren't affected by it being a mixture

Answer 8

A technique that can be used to separate different dyes in an ink

Answer 9

1) Draw a straight line near the bottom of filter paper using a pencil (pencil marks are insoluble) 2) Add a spot of ink to the line and place the paper in a solvent e.g. water or ethanol (some compounds dissolve well in water but others don't) 3) Make sure the ink isn't touching the solvent 4) Place a lid on the solvent container to stop the solvent evaporating

Answer 10

* The solvent will seep up the paper, carrying the ink with it * Each different dye/pigment in the ink will move up the paper at different rates so the dyes will separate out and form a spot in a different place * The insoluble inks in the dye will stay on the baseline * The end result is a pattern of spots called a chromatogram

Answer 11

* If an insoluble product needs to be separated from a liquid reaction mixture. * It can also be used in purification

Answer 12

* The mixture is placed in cone shape filter paper which is in a funnel and a beaker. * The liquid molecules are small enough to pass through the filter paper but the solid product does not and thus, separating them.

Answer 13

Using evaporation or crystallisation

Answer 14

1) The solution is poured into an evaporating dish 2) The solution is slowly heated. The solvent will evaporate and the solution will get more concentrated. Eventually, crystals will start to form 3) The dish is heated until dry crystals are left

Answer 15

The method is quick but can only be used if the salt does not decompose when it is heated unlike in crystallisation.

Answer 16

1) The solution is gently heated in an evaporating dish. 2) Once some of the solvent has evaporated or when crystals start to form, remove the dish from the heat and leave to cool 3) The salt should start to form crystals as it becomes insoluble in the cold, highly concentrated solution 4) Filter the crystals out of the solution and leave them in a drying oven or desiccator to dry

Answer 17

* A process used to separate mixtures which contain liquids. * The main two types of distillation are fractional and simple.

Answer 18

1) Solution is heated. Part of the solution which has the lowest boiling point evaporates first. 2) The vapour is cooled by cold water flowing around the tube (condenser) in which the vapour is travelling through from where it evaporated 3) The vapour condenses and is collected 4) The rest of the solution is left behind in the flask

Answer 19

It can only be used to separate things with very different boiling points

Answer 20

1) The mixture is put in a flask and a fractionating column is put on top. It is then heated. 2) The different liquids evaporate at different temperatures 3) The liquid with the lowest boiling point evaporates first and when the temperature on the thermometer matches the boiling point of this liquid it will reach the top of the column. 4) It will then go through a condenser and be collected 5) The liquids with higher boiling points will only get part the way up the column before condensing and running back down towards the flask 6) Once the first liquid has been collected, the temperature is raised until the next liquid reaches the top of the column and so on

Answer 21

John Dalton concluded atoms were solid spheres and different spheres made up the different elements

Answer 22

He discovered that atoms **were not a solid sphere**. After measuring the charge and mass of an atom, he found that an atom must contain even smaller, negatively charged particles called electrons.

Answer 23

* JJ Thomson's theory was known as the **plum pudding model.** * The theory stated that an atom was a ball of positive charge with electrons stuck in it

Answer 24

**Ernest Rutherford** and his student **Ernest Marsden** using the famous alpha particle scattering experiment

Answer 25

It is the firing of positively charged alpha particles at an extremely thin sheet of gold.

Answer 26

* They expected the particles to pass straight through the sheet or be slightly deflected at most. * This was because the 'plum pudding' theory led them to believe that the positive charge of each atom was spread out throughout the 'pudding' of the atom.

Answer 27

* Most the particles did go through the gold sheet but some were deflected more than expected. * A small number were also deflected backwards. * The plum pudding model couldn't be right

Answer 28

He came up with the nuclear model of an atom

Answer 29

In the model, there is a tiny positively charged nucleus at the centre, where most the mass is concentrated. A 'cloud' of negative electrons surround the nucleus so most the atom is empty space.

Answer 30

* It showed that when the alpha particles came near the concentrated, positive charge of the nucleus, **they were deflected**. * If they were fired directly at the nucleus, they deflected backwards, otherwise they just passed through the empty space.

Answer 31

Scientists realised that the electrons in a 'cloud' around the nucleus of an atom, would be attracted to the nucleus, causing the atom to collapse.

Answer 32

Niles Bohr

Answer 33

* In his model, the atom suggested that the **electrons were contained in shells.** * He proposed that the **electrons orbit the nucleus in fixed shells** and aren't anywhere between. * **Each shell was a fixed distance from the nucleus.**

Answer 34

Bohr's theory was supported by many experiments and it also helped explain the observations that scientists were seeing at the time

Answer 35

The likes of Ernest Rutherford and others, found through experiments that the nucleus can be divided into smaller particles, which each have the same charge as a hydrogen nucleus. These particles were named protons.

Answer 36

* About 20 years after scientists accepted that atoms have nuclei, James Chadwick carried out an experiment which provided evidence for neutral particles in the nucleus which are now called neutrons. * The nuclear model for the atom was similar to the modern day accepted version after this discovery.

Answer 37

* Electrons **always occupy shells** (also called energy levels) * The **lowest energy levels are always filled first** **** * Only **2 electrons are allowed in the first shell****** * **only 8 are allowed in the second and third shells** * atoms like to have full electron shells e.g. noble gases (group 0) * in most atoms electron shells are not full and this makes the atoms want to react

Answer 38

* The number of electrons in each shell of an atom * e.g. Nitrogen has an atomic number of 7 so it must have 7 protons and 7 electrons. * The first shell in the atom can only take 2 so the other five go into the second shell. * Therefore,the electronic structure is 2,5

Answer 39

* They were arranged in order of relative atomic mass. * A periodic pattern was noticed in the properties of the elements. Hence why it was called the periodic table (Newland's Theory of Octaves)

Answer 40

* He took the 50 known elements and put them into his Table of the Elements with various gaps. * However, some of the elements were not arranged in order of atomic mass but were switched if they had a similar property to another element (like iodine and tellurium)

Answer 41

* Some of the gaps indicated the existence of undiscovered elements and allowed Dmitri to predict what those properties. * The gaps were also made to make sure that the elements with similar properties stayed in the same groups.

Answer 42

* They did fit the pattern and it helped confirm Mendeleev's ideas. * Mendeleev made really good predictions about the chemical and physical properties of Ekasilicon which we know today as Germanium.

Answer 43

The columns are made up of elements with similar properties

Answer 44

The columns are called groups

Answer 45

The group number tells you how many electrons are in the outer shell

Answer 46

The rows are called periods and each period number represents the number of shells of electrons.

Answer 47

Positive ions

Answer 48

A full outer shell made via gaining, losing or sharing electrons

Answer 49

* Metals to the bottom have outer shell electrons that are a long way from the nucleus, so have a weaker attraction. * Less is needed to remove the electrons at the bottom * Electron shielding makes it easier to lose the electron too

Answer 50

* Strong and malleable * Good at conducting heat and electricity * Have high boiling and melting temperatures

Answer 51

* The metal elements between group 2 and 3 (don't have a group) * Typical metal properties(dense, strong, shiny) * They can have more than one ion * Transition metal ions are often coloured and so compounds that contain them are colourful * Often good catalysts

Answer 52

All of group 1 Lithium, Sodium, Potassium, Rubidium, Caesium, Francium Form alkalies when reacted with water

Answer 53

* Have one electron in the outer shell which makes them v**ery reactive** and gives them similar properties as they all want to lose the 1 outer electron as they WANT A FULL outer shell * reactivity **increases down the group** as the **distance is greater** from the nucleus (weaker attraction so easier to lose the electron) and there is **higher shielding from more shells** between outer shell and nucleus so easier to lose * Soft and have low density

Answer 54

* Increasing reactivity (the outer electron is more easily lost as the attraction between the nucleus and electron decreases, because the electron is further away from the nucleus the further down the group you go * Lower melting and boiling points * Higher relative atomic mass

Answer 55

* They react vigorously to produce hydrogen gas and metal hydroxides (salts that dissolve in water to produce alkaline solutions). * The more reactive the element, the more violent the reaction

Answer 56

* The amount of energy as you go down the group increases ie. potassium releases enough energy to ignite hydrogen

Answer 57

* Vigorously to form white metal chloride salts. * Reactivity increases down the group so the reaction with chlorine gets more vigorous

Answer 58

Because Group 1 metals react with the oxygen in the air to form a dull metal oxide layer

Answer 59

Li(2)O- lithium oxide

Answer 60

a mixture of sodium oxide and sodium peroxide

Answer 61

A mixture of potassium peroxide and potassium superoxide

Answer 62

They are more reactive e.g. react more vigorously with water, oxygen or Group 7 elements Much less dense, strong or hard and have lower melting points

Answer 63

Non-metals group 7 elements: Fluorine, Chlorine, Bromine, Iodine and Astatine

Answer 64

* Going down the group, the halogens become **less reactive** (outer shell is further distance way from the nucleus), have higher melting and boiling points and have higher relative atomic masses. * They react in fairly similar ways because they all have seven electrons in their outer shell (all form diatomic molecules e.g. most reactive is F₂)

Answer 65

Simple Molecular Structures

Answer 66

ions called **halides** with ionic structures

Answer 67

They will displace the less reactive ones e.g chlorine gas displaces iodine from potassium iodide

Answer 68

* They all have eight electrons in their outer energy level, apart from helium which has two, **giving most of them a full outer-shell**. * They **don't react much at all because their outer shell is energetically stable (more or less inert), strong intermolecular force.** * Monatomic gases (individual atoms) * Colourless gases at room temperature * Non flammable

Answer 69

* The boiling point and relative atomic mass increases down the group * Boiling point increases due to the increase in the number of electrons in each atom leading to greater intermolecular forces

Answer 70

The **electrostatic attraction between oppositely charged ion**s

Answer 71

The **electrostatic between a shared pair of electrons** and the nuclei of the bonding atoms

Answer 72

* His theory only worked for the first 20 elements known at the time * New elements had nowhere to go * Copper was in the same group as Li, Na and K which react with water but copper does not react with water

Answer 73

A property where the substance can dissolve in a certain solution

Answer 74

A property where the substance cannot dissolve in a solution

Answer 75

A solute is a substance(solid) which is dissolved

Answer 76

The liquid that dissolves the solute

Answer 77

A combination of a solute dissolved in a solvent

Answer 78

The sum of all the individual atomic masses for atoms present in the formula of the molecule

Answer 79

* Mobile (where molecules can move (liquid or gas)) * Stationary (where molecules can't move (solid or thick liquid)

Answer 80

The substances in the sample constantly move between phases and an equilibrium is formed

Answer 81

Different chemicals are distributed differently between the two phases, whether it spends more time the stationary or mobile phase

Answer 82

The solvent

Answer 83

The filter paper

Answer 84

* The solubility of the molecule in the solvent * How attracted the molecules are to the filter paper

Answer 85

The ratio between the distance travelled by the dissolved substance and the distance travelled by the solvent

Answer 86

The substance moved further through the stationary phase

Answer 87

distance travelled by substance RF = ----------------------------------------------- distance travelled by solvent

Answer 88

The gas will bubble through limewater and make it go cloudy

Answer 89

A lit splint will make a squeaky pop

Answer 90

A glowing splint will be relighted

Answer 91

* Some chemists thought all elements had been discovered so there was no need for gaps * He put some metals in the same group a non-metals (Bromine with Manganese)

Answer 92

An average atomic mass value which takes into account the abundance of the isotopes of an element.

Answer 93

**35.5** % isotope 1 % isotope 2 ----------------- x mass isotope 1 **+** --------------------- x mass isotope 2 100 100

Answer 94

Cl₂ = faint yellow /green Br₂ = yellow I₂ = orange/brown