Answer: The correct answer is the option: B. An element with eight valence electrons is chemically unstable.
Explanation:
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We will analyze each of the options:
A. The group number of the element provides a clue to the number of valence electrons: it is correct, since it provides the number of valence electrons.
B. An element with eight valence electrons is chemically unstable: this is not correct, since elements with eight electrons in the valence shell cannot react because they already have the last complete shell. Therefore, they are chemically stable.
C. The points must be placed one at a time on each side of the chemical symbol: it is correct, because that is the way to make the point diagram.
D. An atom is chemically stable if all the points are paired: this is correct since this verifies that the point diagram has been done well.
We conclude that the correct answer is the option: B. An element with eight valence electrons is chemically unstable.
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Answer:
quartz (SiO2)n
Explanation:
Melting point is defined as the temperature or point at which the substances change its state from solid to liquid.
Quartz (SiO2)n has high melting point than O2 because Quartz (SiO2)n is found in the form of hard, crystalline mineral that is made up of silicon and oxygen atoms having strong covalent bonds between all the atoms. So, a lot of energy is required to break the bond between the atoms and it has a high melting point.
Hence, the correct answer is quartz (SiO2)n.
Gravity is a force that can used draws everywhere, or everything to the Earth's center.
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-Charlie
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Answer:
e- 7.25 x 10³.
Explanation:
∵ ΔG = -RTlnK,
where, ΔG is the free energy change.
R is the general gas constant (R = 8.324 J/mol.K).
K is the equilibrium constant of the reaction.
- For the reaction: <em>N₂(g) + 3H₂(g) → 2NH₃(g),</em>
K = (PNH₃)²/(PN₂)(PH₂)³ = (0.65)²/(1.9)(1.6)³ = 5.43 x 10⁻².
∵ ΔG = -RTlnK.
∴ ΔG = -(8.314 J/mol.K)(298 K) ln(5.43 x 10⁻²) = 7.218 x 10³ J/mol.
Ions are electrically charged particles formed when atoms lose or gain electrons. They have the same electronic structures as noble gases. Metal atoms form positiveions, while non-metal atoms form negative ions. The strong electrostatic forces of attraction between oppositely charged ions are called ionic bonds.