Explanation:
Thomson's suggested the plum pudding model of the atom in which the atomic space is made up of electrons surround by positive charges.
Rutherford in his gold foil experiment revised the plum pudding model of the atom;
- He discovered that most of the alpha particles passed through the foil while a few of them were deflected back.
- To explain this observation, he suggested the atomic model of the atom.
- In this model, an atom is made up of a small positively charged center where nearly all the mass is concentrated.
- Surrounding the nucleus is the extranuclear part made up of electrons.
Answer:
B
Explanation:
sometimes it can change chemically but not all the time.
Step 1 : Write balanced chemical equation.
CaF₂ can be converted to F₂ in 2 steps. The reactions are mentioned below.
I] 
II] 
The final balanced equation for this reaction can be written as

Step 2: Find moles of CaF₂ Using balanced equation
We have 1.12 mol F₂
The mole ratio of CaF₂ and F₂ is 1:1

Step 3 : Calculate molar mass of CaF2.
Molar mass of CaF₂ can be calculated by adding atomic masses of Ca and F
Molar mass of CaF₂ = Ca + 2 (F)
Molar mass of CaF₂ = 40.08 + 18.998 = 78.08 g
Step 4 : Find grams of CaF₂
Grams of CaF₂ = 
Grams of CaF₂ = 87.45 g
87.45 grams of CaF2 would be needed to produce 1.12 moles of F2.
I have attached an image of the IR spectrum required to answer this question.
Looking at the IR, we can look for any clear major stretches that stand out. Immediately, looking at the spectrum, we see an intense stretch at around 1700 cm⁻¹. A stretch at this frequency is due to the C=O stretch of a carbonyl. Therefore, we know our answer must contain a carbonyl, so it could still be a ketone, aldehyde, carboxylic, ester, acid chloride or amide. However, if we look in the 3000 range of the spectrum, we see some unique pair of peaks at 2900 and 2700. These two peaks are characteristic of the sp² C-H stretch of the aldehyde.
Therefore, we can already conclude that this spectrum is due to an aldehyde based on the carbonyl stretch and the accompanying sp² C-H stretch.