Answer:
Explanation:
The octet rule does not always refer to a stable arrangement of eight valence electrons because there are some element that do not have eight valence electrons yet they are stable. for example;
i) Helium, It has two valence electrons and it is a stable gas.
ii) Boron triflouride (BF3); it has six valence electrons (deficit valence electron) yet it is also stable.
iii) Phosphorus pentachloride (PCl5); it has more than eight valence electron and it is also stable.
For these few reasons it is not always advisable to say octet arrangement refer to stable eight valence electrons.
Answer:
D. He showed that most of an atom's mass was located in the atom's
nucleus.
Explanation:
Ernest Rutherford changed the atomic model because of his experiment which was the gold foil experiment. A beam of alpha particles was aimed at a piece of gold foil, most particles passed through but some were scattered backward which showed that the middle of an atom (nucleus) is the where most of the mass is located.
The two reason behind the invalidity of flame test are false positive and false negative.
while performing the flame test you must have to be accurate otherwise you will get false results may be positive for some element or may be negative in case the element is present. The main reason to get the false positive and false negative is the presence and contamination of sodium.
Answer:
The answer to your question is M = 36.49 g
Explanation:
Data
mass = 8.21 g
volume = 4.8064 L
Temperature = 200°C
Pressure = 1.816 atm
M = ?
Process
1.- Convert temperature to °K
°K = 273 + 200
°K = 473
2.- Calculate the number of moles
n = (PV)/RT
n = (1.816)(4.8064)/(0.082)(473)
n = 0.225
3.- Calculate the molar mass
M --------------- 1 mol
8.21 g ---------- 0.225 moles
M = (1 x 8.21)/0.225
M = 36.49 g
