In a calcium atom, 3) an electron in the third shell has more energy than an electron in the second shell. This is because the shell's distance from the nucleus determines the energy of an electron: the farther the shell, the higher the energy.
The relative energy of the electrons in the shells of a calcium atom would be best described by statement 3, which states: 'An electron in the third shell has more energy than an electron in the second shell.' This is due to the fact that electrons occupy shells (also known as energy levels) around an atom's nucleus, and the further an electron is from the nucleus, the higher its energy. This is because it is closer to the outer environment and has a higher potential energy due to its distance from the atom’s positive core.
In the case of calcium, which has an atomic number of 20, it has four energy levels. This means that an electron in the fourth shell would certainly have more energy than an electron in the first, second, or third shells, and an electron in the third shell would have more energy than one in the second or first shells.
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The cation radii become larger across the period.
Atomic radii increase slightly and then start to decrease.
Atomic radii decrease slightly and then start to increase.
The correct option is D.
Transition metals are those metallic elements that are located in the central block of the periodic table. They exhibit various valency states and they generally have various colors. The atomic radius of an element refers to the measure of the size of its atom. For transition metals, their atomic radii decrease slightly and then start to increase, when one is moving from the left to the right of the periodic table.
Answer : The correct option is, Atomic radii decrease slightly and then start to increase.
Explanation :
Transition metals : It is defined as the element whose atom is ground state or ion in one of the common oxidation states, has incomplete d-subshell.
The general trend of atomic radii of transition metals is :
Generally the atomic radii of d-block elements in a series decreases with increase in atomic number but decreases in atomic size is small after midway that means almost remains same and at the end of the period there is a slight increase in the atomic radii.
Hence, the atomic radii decrease slightly and then start to increase of the transition metals when moving from left to right on the periodic table.
6.21 × 10²² Carbon Atoms
Data Given:
Mass of Butane (C₄H₁₀) = 1.50 g
M.Mass of Butane = 58.1 g.mol⁻¹
Step 1: Calculate Moles of Butane as,
Moles = Mass ÷ M.Mass
Putting values,
Moles = 1.50 g ÷ 58.1 g.mol⁻¹
Moles = 0.0258 mol
Step 2: Calculate number of Butane Molecules;
As 1 mole of any substance contains 6.022 × 10²³ particles (Avogadro's Number) then the relation for Moles and Number of Butane Molecules can be written as,
Moles = Number of C₄H₁₀ Molecules ÷ 6.022 × 10²³ Molecules.mol⁻¹
Solving for Number of Butane molecules,
Number of C₄H₁₀ Molecules = Moles × 6.022 × 10²³ Molecules.mol⁻¹
Putting value of moles,
Number of C₄H₁₀ Molecules = 0.0258 mol × 6.022 × 10²³ Molecules.mol⁻¹
Number of C₄H₁₀ Molecules = 1.55 × 10²² C₄H₁₀ Molecules
Step 3: Calculate Number of Carbon Atoms:
As,
1 Molecule of C₄H₁₀ contains = 4 Atoms of Carbon
So,
1.55 × 10²² C₄H₁₀ Molecules will contain = X Atoms of Carbon
Solving for X,
X = (1.55 × 10²² C₄H₁₀ Molecules × 4 Atoms of Carbon) ÷ 1 Molecule of C₄H₁₀
X = 6.21 × 10²² Atoms of Carbon
of carbon is present in 1.50 g of butane.
Further Explanation:
Avogadro’s number indicates how many atoms or molecules a mole can have in it. In other words, it provides information about the number of units that are present in one mole of the substance. It is numerically equal to . These units can be atoms or molecules.
The formula to calculate the moles of is as follows:
…… (1)
Substitute 1.50 g for the given mass and 58.1 g/mol for the molar mass of in equation (1).
Since one mole of has of . Therefore the formula to calculate the molecules of butane is as follows:
…… (2)
Substitute 0.0258 mol for the moles of and for Avogadro’s number in equation (2).
The chemical formula of butane is . This indicates one molecule of butane has four atoms of carbon. Therefore the number of carbon atoms can be calculated as follows:
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Answer details:
Grade: Senior School
Chapter: Mole concept
Subject: Chemistry
Keywords: 1.50 g, 58.1 g/mol, butane, C4H10, Avogadro’s number, C atoms, molecules, moles, one mole, chemical formula, carbon atoms, molar mass of C4H10, given mass of C4H10.
(2) methane
(3) sodium nitrate
(4) potassium chloride
Compound (3) sodium nitrate contains both ionic and covalent bonds.
Compound (3) sodium nitrate contains both ionic and covalent bonds. Sodium nitrate consists of the ions Na+ and NO3-, where the bond between Na+ and NO3- is predominantly ionic, and the bond within the NO3- ion is covalent. The sodium ion (Na+) donates an electron to the nitrate ion (NO3-), resulting in an ionic bond. However, within the nitrate ion, the nitrogen (N) and oxygen (O) atoms share electrons, forming covalent bonds.
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