Topic 4 Flashcards
What is first ionisation energy?
Ionisation energy is the amount of energy that is required to remove 1 electron from the each atom to form 1 mole of gaseous atom
What is the trend in ionisation energy down group 2?
Down Group 2 = Ionisation energy Decreases
(Deer’s Getting In Danger 🦌🚘 )
Increase shielding → Increase atomic radii → Decrease nuclear charge
What does reactivity mean?
Reactivity is the ability for an element to loose or gain electrons to undergo a chemical reaction with one or more elements or compounds
What is the trend in reactivity down group 2?
Group 2 elements form $M^{2+}$
Down Group 2 = Increase in Reactivity
(Don’t Get In Riots 👮)
Increase in shielding → Increase atomic radii → Decrease in nuclear charge
What are the trends going down group 2?
What is the reactions of Group 2 elements with Oxygen?
G2 would BURN in oxygen producing White Oxides + Bright Flame
(Great Britain Will Oppress 💂♂️⚔️)
$2M_{(s)} + O_{2 (g)}$ → $2MO_{(s)}$
What is the reactions of Group 2 elements with Water?
G2 reacts with water to form metal hydroxide and hydrogen gas
(Not all group 2 elements are insoluble so the (aq) turns into (s) )
(God Will Make Ham ✝️🥓)
$M_{(s)} + H_2O$ → $M(OH){2(aq)} + H{2(g)}$
What are the reactions of group 2 elements with Chlorine?
G2 reacts with chlorine to form solid white chlorides
(Games Cause Seizures 🎮😵💫)
$M_{(s)} + Cl_{2(g)}$ → $MCl_{2(s)}$
What are the pH of group 2 oxides?
- Group 2 oxides would react with water to form Metal Hydroxides
- Which dissolve and dissociate into $OH^-$ making them alkaline
- Alkalinity increases because Solubility increases
- Since Hydroxides are Bases they will Neutralise Dilute Acids to produce salt
Mg** and **Ba** are **exceptions** as they are **slow** or **can’t react** with **water (insoluble)
What is the reaction of group 2 oxides and water
Group 2 oxides react with water to form metal hydroxides
This produces a colourless solution
(Gin Over Wine Make Haters 🍺🍷)
$MO_{(s)} + H_2O_{(l)}$ → $M(OH)_{2(aq)}$
What is the reaction of group 2 oxides and dilute acid?
The group 2 oxides would react with acids to form salts and water
This is an EXO-thermic reaction and turns the white solid to colourless
(Gucci Over Amani Since When? 🎒👝)
$MO{(s)} + 2HCl_{(aq)}$ → $MCl_{2(aq)} + H_2O_{(l)}$
What is the reaction of group 2 hydroxides and dilute acid?
Group 2 hydroxides will neutralise dilute acid to form salt and water
(Good Hats Are Simply Woolly 🎩☁️)
$M(OH){2(aq)} + 2HCl(aq)$ → $MCl_{2(aq)} + H_2O_{(l)}$
What is the trend in solubility in group 2 hydroxides?
As you go down the group solubility of hydroxides increase as hydroxides are single charged negative ions
What are the trends in solubility in group 2 sulfates?
As you go down the group the solubility of sulfates decrease as sulfates are doubly charged negative ions
What is the trend in thermal stability down a group?
- As you go down the group
- Electron density decreases
- As there is more shielding creating a higher ionic radii
- Resulting in less polarisation of the N-O (for group 1 and 2 nitrates) or C-O (for group 1 and 2 carbonates)
- Meaning that there is less distortion on the bond
- Resulting in less energy being required to overcome the bond
What is the reactions for the thermal decompositions of group 1 nitrates?
- Only lithium has greater decomposition
- Where $2LiNO_3$ → $2LiO + NO_2 + O_2$
- The rest has lesser decomposition
- where $2NaNO_3$ → $2NaNO_2 + O_2$
What is the reactions for the thermal decompositions of group 2 nitrates?
- All group 2 nitrates have greater decomposition
- Where $2Be(NO_3)_2$ → $2BeO + 4NO_2 + O_2$
What are the reactions of the group 1 carbonates?
What are the reactions for group 2 carbonates?
What are the flame colours for group 1 and 2?
Why are there flame colours?
- Electrons would absorb the heat energy and excite to a higher energy level
- After a short time they would return back to their original energy level
- This would releases energy which can be in the visible light spectrum (if not then there would no colour change)
How would you carry out a flame test?
Flame test practical
- Dip the nichrome wire into deionised water
- Then flame the wire
- Then put into HCl
- Then flame again and put into sample solid
- Put into flame and observe the colour using a spectrograph
What is the trend in reactivity down group 7?
Less Reactive down group
- More shielding + Higher Ionic radii
- Weaker forced of attraction between the nucleus and the outer electrons
- Less able to attract electrons meaning that its less reactive
What is the the trend in electronegativity down group 7?
- Nuclear charge decreases down the group
- As the ionic radii increases down the group as well as shielding
- Meaning electronegativity decreases
