Answer:
Atomic mass of E is 128.24
Explanation:
- The percentage composition by mass of an element in a compound is given by dividing the mass of the element by the total mass of the compound and expressing it as a percentage.
- In this case; the compound Bi₂E₃
Percentage composition of bismuth = 52.07%
Percentage composition of E = 47.93%
Mass Bismuth in the compound is (2×208.9804) = 417.96 g
Therefore,
To calculate the atomic mass of E
52.07% = 417.96 g
47.93% = ?
= (47.93 × 417.96 ) ÷ 52.07 %
= 384.729
E₃ = 384.729
Therefore; E = 384.729 ÷ 3
= 128.24
The atomic mass of E is 128.24
Answer:
Formation. When the solar system settled into its current layout about 4.5 billion years ago, Earth formed when gravity pulled swirling gas and dust in to become the third planet from the Sun. Like its fellow terrestrial planets, Earth has a central core, a rocky mantle and a solid crust.
<span>because p6 will be the group 8. You have to count the 2 electrons from the "s" block that are Group I and Group II
Group I s1
Group II s2
Group III s2 p1
Group IV s2 p2
Group V s2 p3
Group VI s2 p4
Group VII s2 p5
Group VIII s2 p6</span>
Explanation :
As we know that Mendeleev arranged the elements in horizontal rows and vertical columns of a table in order of their increasing relative atomic weights.
He placed the elements with similar nature in the same group.
According to the question, the atomic weight of iodine is less than the atomic weight of tellurium. So according to this, iodine should be placed before tellurium in Mendeleev's tables. But Mendeleev placed iodine after tellurium in his original periodic table.
However, iodine has similar chemical properties to chlorine and bromine. So, in order to make iodine queue up with chlorine and bromine in his periodic table, Mendeleev exchanged the positions of iodine and tellurium.
As we know that the positions of iodine and tellurium were reversed in Mendeleev's table because iodine has one naturally occurring isotope that is iodine-127 and tellurium isotopes are tellurium-128 and tellurium-130.
Due to high relative abundance of tellurium isotopes gives tellurium the greater relative atomic mass.
