The periodic Table (3) ✅ Flashcards
Who + when developed the modern periodic table
Dmitri Mendeleev, 1869
What are the 5 main properties of Dmitri Mendeleev’s periodic table
- arranged in order of increasing atomic mass
- Left gaps for undiscovered elements
- No noble gases
- No transition metal block
- No actinides or lanthanides
What are the 5 main properties of the modern periodic table
- arranged in order of increasing atomic number
- no gaps left
- Noble gases present
- Block of transition metals between group 2+3
- actinides and lanthanides present
what are the group 1 elements called?
The alkali metals - the most reactive metals
what are the group 7 elements called?
The halogens - the most reactive non-metals
what are the group 0 elements called?
The noble gases - unreactive non metals
what are the group 2 elements called?
Alkaline earth metals - less reactive than group 1
what is the block of elements between group 2+3 called?
the transition metals - form coloured compounds and their unreactive metals
what is the most reactive metal
francium
what is the most reactive non metal
fluorine
what are the two semi metals
Silicon, germanium
what are the vertical columns on the periodic table called
groups
what are the horizontal rows on the periodic table called
periods
floats, moves, bubbles, heat, disappears ,solution, universal indicator
what observations are observed when Lithium (Li) reacts with water
metal floats, moves on surface, bubbles of gas, heat released, Li disappears, colourless solution forms, universal indicator turns purple
what is the equation for Lithium reacting with water
2Li + 2H2O –> 2LiOH + H2
what observations are observed when Sodium (Na) reacts with water
metal floats, moves on surface, bubbles of gas, heat released, Na melts and forms ball, Na disappears, colourless solution forms, universal indicator turns purple
what is the equation for sodium reacting with water
2Na + 2H2O —> 2NAOH + H2
what observations are observed when Potassium (K) reacts with water
metal floats, moves on surface, burns with lilac flame, heat released, bubbles of gas, K disappears, colourless solution forms, universal indicator turns purple
what is the equation for potassium reacting with water
2K + 2H20 –> 2KOH + H2
Name 5 safety precautions we always take when using alkali metals
- safety screen
- hair up and goggles worn
- metal handled with tweezers
- small pieces used
- large volume of water
how are alkali metals stored and why?
under oil - to prevent reaction with oxygen and moisture in the air
how many electrons do alkali metals have in their outer shell
(group 1)
1
when alkali metals react they lose how many electrons?
and form what type of bond with non-metals
one
ionic bonds
name 3 characteristics of alkali metals
soft, shiny, tarnish quickly
What do alkali metals form when they react?
A positive ion (cation)
Alkali metals lose one electron during the reaction.
Why do alkali metals have similar chemical properties?
They react by losing one electron to form stable cations
This results in a full outer shell of electrons.
What charge do the cations formed by alkali metals carry?
A single positive charge
This charge reflects the loss of one electron.
Fill in the blank: Alkali metals lose one electron to form a _______.
positive ion (cation)
This process leads to stability in the ion.
What characteristic of cations contributes to their stability?
A full outer shell of electrons
This is a common trait in stable ions.
What is the color of most group 1 compounds?
White
Do most group 1 compounds dissolve in water?
Yes
What type of solutions do most group 1 compounds give when dissolved in water?
Colourless solutions
What are group 7 elements known as?
Halogens
Halogens are reactive non-metals.
How many electrons do halogens have in their outer shell?
7 electrons
This electron configuration contributes to their reactivity.
What is the valency of halogens?
1
This means they need one electron to achieve stability.
What do halogens need to be stable?
One electron
Acquiring one electron allows them to achieve a full outer shell.
In what form do halogens exist when unreacted?
Diatomic molecules
Examples include Cl2, Br2, I2.
What is an example of a diatomic molecule formed by a halogen?
Cl2
Other examples include Br2 and I2.
What happens to iodine when heated?
The grey-black solid changes to a purple vapour.
What is the process called when a solid changes directly to a gas?
Sublimation.
What occurs when iodine cools after being heated?
It changes back to grey-black crystals.
True or False: Sublimation is the process of a solid turning into a liquid.
False.
Fill in the blank: The grey-black solid iodine changes to a _______ vapour when heated.
purple
what does aquinas mean
mixed with water
what happens when iodine or bromine (halogens) is mixed with sodium chloride solution
no reaction
what happens when sodium bromide solution is mixed with chlorine
colourless solution turns orange
what happens when sodium bromide solution is mixed with iodine
no reaction
what happens when sodium iodide solution is mixed with chlorine or bromine
colourless solution turns brown
reacitivity
What trend in reactivity is observed in group 7 halogens?
Reactivity decreases going down group 7.
What does a more reactive halogen do to a less reactive halogen in an aqueous solution?
A more reactive halogen will displace a less reactive halogen from its salt solution.
Why do halogens have similar chemical properties?
Because when they react, an atom gains one electron to form a negative ion (anion) with a full outer shell of electrons.
What charge does a stable halogen ion have?
A single negative charge.
Fill in the blank: The ion formed by halogens after gaining an electron is called a _______.
negative ion (anion).
True or False: All halogens react by losing an electron.
False.
What happens to the electron configuration of a halogen atom when it reacts?
It gains one electron to achieve a full outer shell.
What happens to the number of electron shells as you move down Group 7?
The atoms have more shells of electrons
How does the distance of the outermost shell from the nucleus change down Group 7?
The outermost shell is further from the positive attraction of the nucleus
What effect does the increased distance from the nucleus have on the attraction of incoming electrons?
The force of attraction decreases
What is the trend in reactivity as you move down Group 7?
Reactivity decreases
True or False: The reactivity of elements in Group 7 increases as you go down the group.
False
What is the test for chlorine?
universal indicator paper turns red then bleaches white
What are Group 0 elements known as?
Noble gases
Group 0 elements are characterized by their lack of reactivity due to having a complete valence shell.
What is a defining characteristic of noble gases?
Unreactive non-metals
Noble gases do not easily form chemical compounds with other elements.
physical properties of transition metals
high melting point (except mercury)
high density
low reactivity - some react with steam
physical properties of Group 1 metals
low melting point
Low density
very reactive with water
