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Answer:</h3>
Al- [Ne] 3s²3p¹
As- [Ar] 4s²3d¹⁰ 4p³
Explanation:
- Electron configuration of an element shows the arrangement of electrons in the energy levels or orbitals in the atom.
- Noble-gas configuration involves use of noble gases to write the configuration of other elements.
- This is done by identifying the atomic number of the element and then identifying the noble gas that comes before that particular element on the periodic table.
- Aluminium: The atomic number of Al is 13. The noble gas before Aluminium is Neon which has 10 electrons. Therefore the remaining 3 electrons fills up the 3s and 3p sub orbitals.
- Thus, the noble-gas configuration of Al is [Ne] 3s²3p¹
2. Arsenic, Atomic number is 33
- Noble gas before Arsenic is Ar,. Argon has 17 electrons, then the remaining electrons fills up the 4s, 3d and 4p sub-orbitals.
- Thus, the noble-gas configuration of As is [Ar] 4s²3d¹⁰ 4p³
Answer: c. elements in the same row of the periodic table
Explanation: It kind of represents a graph of the periodic table
Matter is anything that has mass and occupies space, It can exist in 3 states, or phases: solid, liquid, and gas.
Solid molecules are closely packed together and retain a fixed shape.
Liquid molecules aren't packed very closely, and take the shape of the bottom of the container.
Gas molecules are far apart and fill the container
completely.
Answer:
25.89 × 10²³ molecules
Explanation:
Given data:
Mass of CoCl₂ = 560 g
Number of molecules present = ?
Solution:
Number of moles of CoCl₂:
Number of moles = mass/molar mass
Number of moles = 560 g/ 129.84 g/mol
Number of moles = 4.3 mol
Avogadro number:
The given problem will solve by using Avogadro number.
It is the number of atoms , ions and molecules in one gram atom of element, one gram molecules of compound and one gram ions of a substance. The number 6.022 × 10²³ is called Avogadro number.
1 mole = 6.022 × 10²³ molecules
4.3 mol × 6.022 × 10²³ molecules /1 mol
25.89 × 10²³ molecules
