Answer:
- <em>1. The mass of an atom is concentrated at the nucleus.</em>
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- <em>3. Positive charge is condensed in one location within the atom.</em>
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- <em>4. The majority of the space inside the atom is empty space.</em>
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- <em>6. The atom contains a positively charged nucleus.</em>
Explanation:
When J.J Thmpson discovered the electron, he depicted the atom by the plum pudding model: a solid dough of homogeneously distributed positive charge (the pudding) containing negatively charged electrons (the plums).
Later, the scientist <em>Ernest Rutherford</em>, with its experiment of the gold foil experiment showed that the subatomic particles where not all concentrated in a solid part.
When a thin gold foil was bombarded with alpha particles (positively charged nuclei of helium atoms), most of the particles went through the gold sheet, with little deviation, but some particles bounded with a high deviation.
Such few high deviations were explained by the fact that there was a heavy region in the atom (the core or nucleus) with the positive charge that repelled the positively charged alpha particles.
Thus, <em>the mass of the atom was conentrated at the nucleus</em> (choice 1), where the positive charge is distributed in one location, which is the nucleus (not over the entire atom, just on the nucleus) discarding the choice number 2 (that a positive charge is spread equally over the atom) and proving choices 3 (<em>the positive charge is condensed in one location within the atom</em>) and 6 (<em>the atom contains a positively charged nucleus</em>).
Since most of the particles indeed went through the nucleus, this nucleus has to occupy little space, and most of the atom was empty space, proving choice 4 (<em>the majority of the space inside the atom is empty space</em>).
Answer: 3. No displacement, zinc is most reactive.
4. Calcium Chloride, Calcium is most reactive.
5. No displacement, Copper is most reactive
6. No displacement, Calcium is most reactive
7. Hydrogen Oxide, Hydrogen is most reactive
8. Carbon oxide, Carbon is most reactive
9. No displacement, Aluminum is most reactive
10. Potassium Kryptide + Lead, no displacement, Potassium is most reactive.
It’s definitely magnesium but it may not be
Answer:
0.26×10²³ molecules
Explanation:
Given data:
Volume of gas = 1.264 L
Temperature = 168°C
Pressure = 946.6 torr
Number of molecules of gas = ?
Solution:
Temperature = 168°C (168+273= 441 K)
Pressure = 946.6 torr (946.6/760 = 1.25 atm)
Now we will determine the number of moles.
PV = nRT
P= Pressure
V = volume
n = number of moles
R = general gas constant = 0.0821 atm.L/ mol.K
T = temperature in kelvin
n = PV/RT
n = 1.25 atm ×1.264 L / 0.0821 atm.L/ mol.K ×441 K
n = 1.58 /36.21 /mol
n = 0.044 mol
Now we will calculate the number of molecules by using Avogadro number.
1 mol = 6.022×10²³ molecules
0.044 mol × 6.022×10²³ molecules/ 1mol
0.26×10²³ molecules
