C2:Periodic Table Flashcards
How were elements classified in the early 1800s?
- By their atomic weight
- By their physical and chemical properties.
Describe two changes Mendeleev made to early periodic tables…
- In 1869 he ordered elements in terms of similar properties
- He predicted properties of undiscovered elements,like germanium.
What are the trends of group 1 and group 7?
- group 1 elements react more virgorously as you go down.
- group 7 elements reactivity decreases as you go down the groups.
Using periodic table,state how many electrons beryllium has in its outer shell…
-2 electrons
Why would chlorine react similarly to bromine?
-Because they are in the same group es eachother.
Suggest what ions potassium forms,if for example Sodium forms 1+ ioms.
-K+ Ions
What do metal elements form when they react?
- positive ions
- (non metals dont form positive ions)
Iodine generally reacts by forming negative ions,is iodine a metal or a non metal?
-Iodine is a non-metal
What are some properties of metals?
- They are strong,but can be malleable.
- They are great at conducting heat and electricity.
- They have high boiling and melting points.
State whether metals generally form poitive ions or negative ions.
Explain why they form these ions with reference to position in periodic table.
- Metals generally form positive ions
- Metals to the left of the periodic table dont have many electrons to remove.
- Metals at the bottom of the table have outer electrons which are far from nucleus so feel a weaker attraction.
- Meaning not much energy is needed to remove electrons so its feasible for the elements to react to form positive ions.
What happens when Group 1 metals are put in water?
- They react vigorously,the more down the group the greater reaction
- Hydrogen is produced for potassium and below in the group
- Hydroxides are formed that dissolve in water to give alkaline solutions.
Write a word equation for the reaction between lithium and water…
Lithium + Water –> lithium hydroxide + hydrogen
What do the trends for Group 1 as you go down include?
- Increase in reactivity
- Lower melting and boiling points
- Higher relative atomic mass
As you go down group 7 the halogens….
- become less reactive
- have higher melting and boiling points
- have higher relative atomic masses
Why do Group 7 elements get less reactive as you go down the group?
-Because its harder to gain an extra electron,because the outer shell is further from the nucleus.
What occurs when Halogens bond with Metals
Non metals with Metals
- The halogens from 1- ions called Halides (F-,Cl-,Br- and I-),for example Na+Cl-.
- These compound have ionic structures were for example Na would lose an electron(dot) and join Cl (with crosses).
How can a displacement reaction occur?
-When a more reactive halogen and the salt of a less reactive one react together.
%
-e.g chlorine can displace bromine and iodine from an aqueos solution of its salt (a bromide or iodide)
What are some features of Noble Gases (Group 0) …
- They are inert,meaning they are stable and dont react very much.
- They exist as monoatomic gases-single atoms not bonded to each other
- They are non-flammable
- They all have eight electrons in thr outer energy level,apart from helium which has two.
What are some patterns in the properties of the Noble Gases?
-The boiling points of the noble gases increase as you move down the group along with increasing relative atomic mass.
Why does boiling point increase in Group 0 as you move down?
-Due to an increase in the number of electrons in each atom leading to greater intermolecular forces between them,needing to be overcome.
Radon and Krypton have boiling points of -62 °C and -153 °C
Predict the boiling point of xenon…
-Xenon comes in between radon and krypton,so boiling point woukd be halfway between their boiling points
-(-152) + (-62) = -215
-215/2 = 107.5 = 108°C
Xenon boiling point around 108°C
Does Xenon or Neon have a higher boiling point?
-xenon has a higher boiling point
