Element at Extreme Left In Periodic Table:
The elements of Group I-A (1) are present at extreme left of the periodic table. They are called as Alkali Metals. Alkali Metals are strong metals. These elements can easily loose their valence electron. The valence shell electronic configuration of these elements is,
ns¹
where n is principle quantum number, which shows main energy level or shell. These metals can gain Noble gas configuration (stable configuration) either by loosing one electron or by gaining seven or more electrons. As it is quite reasonable to loose one electron instead of gaining seven or more electrons so these element easily loose one electron to gain noble as configuration. The Metallic character decreases along the period from left to right. So Group II-A (2) are second most metallic elements and so on. These metals at extreme left mainly exist in solid form.
Element at Extreme Right In Periodic Table:
Elements present at extreme right of the periodic table lacks the properties of metallic character and act as non-Metals. They have almost complete outermost shell or have the deficiency of one or two electrons. They are not as hard as metallic elements and they exist with complete octet like in Noble gases, or deficient with one electron (Halogens) or two electrons (oxygen group). These elements tend to gain or accept electron if their valence shell is deficient with required number of elements. Like the valence electronic configuration of Halogens is,
ns², np⁵
So, Halogens readily accept one electron and attain noble gas configuration. Elements at extreme left exist mainly in gas phase.
Answer:
1.63ₓ10⁻⁶ g of U
139.03 g of H
0.385 g of O
141.8 g of Pb
Explanation:
In first place, we need to convert the number of atoms to moles, as we know that 1 mol of anything occupies 6.02×10²³ particles
Therefore:
4.12×10¹⁵ atoms of U . 1 mol / 6.02×10²³ atoms = 6.84×10⁻⁹ moles of U
8.37×10²⁵ atoms of H . 1 mol /6.02×10²³ atoms = 139.03 moles of H
1.45×10²² atoms of O . 1 mol /6.02×10²³ atoms = 0.0241 moles of O
4.12×10²³ atoms of Pb . 1 mol /6.02×10²³ atoms = 0.684 moles of Pb
Moles . Molar mass = Mass (g)
6.84×10⁻⁹ moles of U . 238.03 g/mol = 1.63ₓ10⁻⁶ g of U
139.03 moles of H . 1 g/mol = 139.03 g of H
0.0241 moles of O . 16 g/mol = 0.385 g of O
0.684 moles of Pb . 207.2 g/mol = 141.8 g of Pb
Answer: 3.01 x 10^24 atoms
Explanation:
Based on Avogadro's law:
1 mole of any substance has 6.02 x 10^23 atoms
So, 1 mole of water = 6.02 x 10^23 atoms
5 moles of water = Z atoms
To get the value of Z, cross multiply
Z x 1 mole = (6.02 x 10^23 atoms x 5 moles)
Z•mole = 30.1 x 10^23 atoms•mole
Divide both sides by 1 mole
Z•mole/1 mole = 30.1 x 10^23 atoms•mole/ 1 mole
Z = 30.1 x 10^23 atoms
[Place the value of Z in standard form]
Z = 3.01 x 10^24 atoms
Thus, there are 3.01 x 10^24 atoms in 5 mole of water
Answer:
Helium is the second element on the periodic table. It is located in period 1 and group 18 or 8A on the righthand side of the table. This group contains the noble gases, which are the most chemically inert elements on the periodic table. Each He atom has two protons and usually two neutrons and two electrons.
Explanation:
thoughtco.com
The particles that make up the atomic nucleus of all atoms are both protons and neutrons.
