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larisa86 [58]
3 years ago
9

Fireworks that contain metallic salts such as sodium, strontium, and barium can generate bright colors. a technician investigate

s what colors are produced by the metallic salts by performing flame tests. during a flame test, a metallic salt is heated in the flame of a gas burner. each metallic salt emits a characteristic colored light in the flame. 72 explain why the electron configuration of 2-7-1-1 represents a sodium atom in an excited state. [1]
Chemistry
1 answer:
Tasya [4]3 years ago
7 0

Answer is: The electrons moved from the second energy level to the fourth.

Atomic number (Z) of sodium is 11, it means that it has 11 protons and 11 electrons, so atom of sodium is neutral.

Electron configuration of sodium atom in a ground state:

₁₁Na 1s² 2s² 2p⁶ 3s¹ or 2-8-1-0.

In a ground state of sodium atom, fourth energy level is empty.

In a excited state electron from second energy level (2s² 2p⁶) moves to fourth energy level.

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3 years ago
Which is the correct Lewis structure for carbon monoxide?
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3 years ago
Is a burning log an exothermic or endothermic event if the log is the system?
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6 0
3 years ago
In an experiment, hydrochloric acid reacted with different volumes of sodium thiosulfate in water. A yellow precipitate was form
erastovalidia [21]

Answer:

The time taken for the cross mark to disappear decreases steadily down the column.

Explanation:

Now if we look at the data provided, we will discover that the volume of the HCl was held constant while the volume of the thiosulphate was increased steadily and the volume of water decreased steadily.

Recall that a system is more concentrated when it contains less volume of water and more volume of reactants. Hence as the volume of water in the system is being reduced, the concentration of reactants is increased.

It has been established that an increase in the concentration of reactants lead to an increase in the rate of reaction. The disappearance of the cross shows the completion of the reaction between HCl and thiosulphate. The faster or slower the cross disappears, the faster or slower the rate of reaction.

Since increase in concentration of reactants increases the rate of reaction, it is observed that as the volume of the thiosulphate increases (reactant concentration increases) the cross disappears faster (rate of reactant increases). Hence as the volume of thiosulphate increases, it takes a shorter time for the cross to disappear. This implies that the time column in the table (refer to the question) will decrease steadily as the volume of thiosulphate increases.

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3 years ago
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