C4.1 Flashcards
- What do atoms of each element have?
-atoms of each element have different proton numbers, as it is the proton number which determines what element it is
- What happens when you arrange the elements in order of their proton numbers?
-it gives repeating patterns in the properties of elements
- What happened to early attempts to find connections between the chemical properties of the elements and their relative atomic mass?
-they were dismissed by the scientific community
- Who were significant individuals in the history of the development of the Periodic Table?
- Döbereiner
- Newlands
- Mendeleev
- What were the elements originally arranged by? Why?
-relative atomic mass as that was the only thing they could measure
- What contribution did Döbereiner have to the development of the Periodic Table?
-1828
-triads:
similar chemical properties
middle element of triad had average ram of the other two
- What contribution did Newlands have to the development of the Periodic Table?
- 1865
- arranged in order of ram
- octaves (each 8th element had similar properties)
- third row broke down as he didn’t leave gaps
- Why was Newlands work criticised?
- groups contained elements that didn’t have similar properties
- he mixed up metals and non-metals
- he didn’t leave gaps for undiscovered elements
- What contribution did Mendeleev have to the development of the Periodic Table?
- 1869
- arranged in order of ram
- left gaps so elements had similar properties in vertical rows
- gaps left for undiscovered elements
- How did Mendeleev use his Periodic Table to predict the existence of unknown elements?
- he left gaps for undiscovered elements
- newly discovered elements fit into gaps= supports his arrangement
- What do all the elements in each group have?
The elements in a group have similar properties
- What is a group of elements?
A group of elements is a vertical column in the Periodic Table
- What is a period?
A period is a row of elements in the Periodic Table
- What elements on the periodic table are metal and non-metal?
Metals are on the left side of a diagonal line from the bottom of boron to the bottom of astatine, non-metals are on the right
- What are Group 1 metals also known as?
The alkali metals
- Which elements are in group 1? What are their chemical symbols?
- lithium= Li
- sodium= Na
- Potassium= L
- What is a visible property of group one metals?
The alkali metals are shiny when freshly cut but tarnish rapidly in moist air due to reaction with oxygen
- What are patterns in Group 1 metals?
DOWN THE GROUP
- more reactive
- higher density
- lower melting point
- lower boiling point
- Why does REACTIVITY INCREASE down group 1 metals?
-Wants to lose 1 electron to be a full shell
Increased atom size= outer electron further away from nucleus= more easily lost
- Why does DENSITY INCREASE down group 1 metals?
-Because the atoms are bigger so have more mass
- Why does MELTING/BOILING POINT DECREASE down group 1 metals?
- Increased atom size= increase in distance of ions to delocalised electrons= weaker metallic bond (electromagnetic force is more spread out)
- What is the reaction between lithium and water like?
- floats on water
- gently fizzes and gives of hydrogen
- dissolves= lithium hydroxide
- What is the reaction between sodium and water like?
- floats on water
- heat= melts= silvery ball
- hydrogen given off
- dissolves= sodium hydroxide
- What is the reaction between potassium and water like?
- floats on water faster
- heat= melts= silvery ball
- hydrogen given off, and ignited to as enough energy= lilac flame
- dissolves= lithium hydroxide
- What is formed when alkali metals react with water?
-an alkaline solution of a hydroxide of the metal with the formula (M)OH [‘metal’ hydroxide]
- What are examples of this hydroxide solution?
- lithium hydroxide (LiOH)
- sodium hydroxide (NaOH)
- potassium hydroxide (KOH)
- What happens in the reaction between alkali metals and chlorine?
alkali metals react vigorously with chlorine to form colourless, crystalline salts with the formula (M)Cl [‘metal’ chloride]
- What are examples of colourless crystalline salts produced in the reaction between alkali metals and chlorine?
- lithium chloride (LiCl)
- sodium chloride (NaCl)
- potassium chloride (KCl)
- What happens to the reactivity and properties of alkali metals as the group is descended?
-more reactive
Wants to lose 1 electron to be a full shell
Increased atom size= outer electron further away from nucleus= more easily lost
- What are examples to show that the alkali metals become more reactive as the group is descended?
-more violent the reaction between an alkali metal and cold water, the more reactive it is
- What are the hazard symbols?
-explosive, toxic, corrosive, oxidizing, and highly flammable
- What does EXPLOSIVE mean? What is an example?
- can explode
- e.g. some peroxides
- What does TOXIC mean? What is an example?
- can cause death if swallowed, breathed in, or absorbed through skin
- e.g. Hydrogen cyanide
- What does CORROSIVE mean? What is an example?
- attacks and destroys living tissues, like eyes and skin
- e.g. concentrated sulphuric acid
- What does OXIDISING mean? What is an example?
- provides oxygen so other materials can burn more
- e.g. liquid oxygen
- What does HIGHLY FLAMMABLE mean? What is an example?
- catches fire easily
- e.g. petrol
- What are the necessary precautions when working with Group 1 metals and alkalis?
- stored in oil as react vigorously with water
- fire extinguisher close as reactive and spontaneously combust
- don’t touch it as can react with sweat= heat and corrosive hydroxide
- apparatus needs to be dry as reacts with water
- can’t touch skin or eyes as alkaline solutions are corrosive
- What are Group 7 metals also known as?
The halogens
- Which elements are in group 7? What are their chemical symbols?
Chlorine- Cl2
Bromine- Br2
Iodine- I2
- What are the states of halogens at room temperature and pressure?
Fluorine - gas
Chlorine - Dense gas
Bromine - Volatile liquid
Iodine - Crystalline solid
- What are the colours of these halogens in their normal physical state at room temperature and as gases?
Fluorine - Yellow
Chlorine - green
Bromine - Orange
Iodine - Dark grey (gas= Purple vapour)
- What are the molecules of halogens?
The halogens consist of diatomic molecules
- What are patterns in Group 7 elements?
What happens as you go DOWN the group:
-Become less reactive
Wants to gain 1 electron to be a full shell
Increased atom size= outer electron further away from nucleus= harder to gain
-Have a higher melting/ boiling point
Van der Waals dispersion forces
- What happens to the reactivity of halogens as you go down the group?
-reactivity decreases
- What are examples that show that reactivity of halogens decreases as you go down the group?
- reactions with alkali metals become less vigorous down the group
- reactions with iron become less vigorous down the group
- displacement reactions shows which elements (ones further up) are more reactive than others
- What happens in the reaction between a halogen and an alkali metal (to show decreasing reactivity down the group)?
-halogen + alkali metal (e.g. lithium, sodium, potassium)= salts called metal halides (e.g. sodium chloride, potassium bromide, lithium iodide)
- What happens in the reaction between a halogen and iron (to show decreasing reactivity down the group)?
-halogen + iron= coloured solids called iron halides
- What happens in displacement reactions with halogen (to show decreasing reactivity down the group)?
-more reactive element from compound displaces less reactive element (pushes it out)
- What are the necessary precautions when working with the halogens?
- don’t get in body as chlorine+ iodine= toxic
- careful with fluorine as is most reactive
- avoid contact with skin as liquid bromine is corrosive
- in fume cupboard as they have poisonous vapours which irritate eyes and lungs
- What must charges add up to in compounds?
0
- What are examples of halides?
- chlorides
- bromides
- iodides
