Atomic size decreases in a period but the ionization energy and electronegativity increases across a period.
<h3>
Describe the trends in the atomic size, ionization energy and electronegativity?</h3>
Atomic radius decreases across a period because of nuclear charge increases whereas atomic radius of atoms generally increases from top to bottom within a group because there is again an increase in the positive nuclear charge.
Ionization energy increases when we move from left to right across an period and decreases from top to bottom.
Electronegativity also increases from left to right across a period and decreases from top to bottom.
So we can conclude that atomic size decreases in a period but the ionization energy and electronegativity increases across a period.
Learn more about Electronegativity here: brainly.com/question/24977425
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Answer:
ΔH of the reaction is -802.3kJ.
Explanation:
Using Hess's law, you can know ΔH of reaction by the sum of ΔH's of half-reactions.
Using the reactions:
<em>(1) </em>Cgraphite(s)+ 2H₂(g) → CH₄(g) ΔH₁ = −74.80kJ
<em>(2) </em>Cgraphite(s)+ O₂(g) → CO₂(g) ΔH₂ = −393.5k
J
<em>(3) </em>H₂(g) + 1/2 O₂(g) → H₂O(g) ΔH₃ = −241.80kJ
The sum of (2) - (1) produce:
CH₄(g) + O₂(g) → CO₂(g) + 2H₂(g) ΔH' = -393.5kJ - (-74.80kJ) = -318.7kJ
And the sum of this reaction with 2×(3) produce:
CH₄(g) + 2 O₂(g) → CO₂(g) + 2H₂O(g) And ΔH = -318.7kJ + 2×(-241.80kJ) =
<em>-802.3kJ</em>
Like all objects, rockets are governed by Newton's Laws of Motion. The First Law describes how an object acts when no force is acting upon it. So, rockets stay still until a force is applied to move them. Newton's Third Law states that "every action has an equal and opposite reaction".
The atomic number is always equal to the number of protons. It will be equal to the number of elections also if the atom has a neutral charge.
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Elements of Group 1 and group 2 in the periodic
table contain elements so reactive that they are never found in the free state
<u>Explanation</u>:
The metals in group 1 of periodic table consisting of 'alkali metals' which include lithium, potassium, sodium, rubidium, Francium and caesium. They are highly reactive because they have low ionisation energy and larger radius. The group 2 metals consist of 'alkaline earth metals' which include calcium, strontium, barium, beryllium, radium and magnesium. These alkaline earth metal have +2 oxidation number, hence are highly reactive.
These both group metals are mostly reactive and so are never found in a free state. When they are exposed to air they would immediately react with oxygen. Hence, are stored in oils to avoid oxidation.
