Answer:
Francium (Fr)
Explanation:
Looking at the periodic table, Francium has 7 energy levels as it is in the 7th Period and is in the 1st Group (meaning it has one electron in the outermost shell) which suggests that it has one valence electron.
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The alkali metals can't exist alone in nature because of incomplete outermost shell of alkali metals.
<h3>What are the properties of alkali metals?</h3>
The alkali metals have the high thermal and electrical conductivity. It has high lustre, ductility, and malleability as compared to other materials. Each alkali metal atom has one electron in its outermost shell which make more reactive.
So we can conclude that the alkali metals can't exist alone in nature because of incomplete outermost shell of alkali metals.
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Answer:
<h3>The answer is 3.0 g/mL</h3>
Explanation:
The density of a substance can be found by using the formula
From the question
mass = 15 g
volume = 5 mL
We have
We have the final answer as
<h3>3.0 g/mL</h3>
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Answer: False
Explanation:
Since the given equation is not balanced properly.
Since oxygen and hydrogen atoms are not balanced.
There should be 6 H2O (g) molecules and 14 mol H2 (g)
Answer: (2) decreasing the concentration of HCl(aq) to 0.1 M
Explanation: Rate of a reaction depends on following factors:
1. Size of the solute particles: If the reactant molecules are present in smaller size, surface of particles and decreasing the size increases the surface area of the solute particles. Hence, increasing the rate of a reaction.
2. Reactant concentration: The rate of the reaction is directly proportional to the concentration of reactants.
3. Temperature: Increasing the temperature increases the energy of the molecules and thus more molecules can react to give products and rate increases.
(1) Increasing the initial temperature to 25°C will increase the reaction rate.
(2) Decreasing the concentration of HCl(aq) to 0.1 M will decrease the reaction rate due to lesser concentration.
(3) Using 1.2 g of powdered Mg will increase the reaction rate due to large surface area.
(4) Using 2.4 g of Mg ribbon will increase the reaction rate due to high concentration of reactants.
