Answer:
Nitrogen is a chemical element that has the symbol N and atomic number 7 and atomic mass 14.00674µ.
Explanation:
In this question we are asked to round off the figure 0.02056 to three significant figures.
We are given with four options to chose best out of four
a) 0.0205
b) 0.0206
c) 0.021
d) 0.020
In this question, option (b) is correct i.e. 0.0206.
There are four significant rules, we should keep in mind during round off:
- Non-zero digits are so significant
- Zeros between two non-zero digits are significant
- Leading zeros are not significant
- Trailing zeros are important only if the number contains a decimal point
To know more about Round off:
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The atoms that the electrons leave behind become positive ions, and the interaction between such ions and valence electrons gives rise to the cohesive or binding force that holds the metallic crystal together
The isotope is identified as 58 Fe²⁺, where 58 is the mass number of the isotope.
Explanation:
In this problem, there is difference in the number of protons and electrons, but the electron number should not vary in a stable isotope. As isotopes are meant to have difference in number of neutrons leading to change in the mass number. So this means, in the present case the isotope is in oxidized state as the number of electrons is less than the number of protons. This indicates that the isotope is in +2 oxidation state, since the difference in the number of protons and electrons is 2.
Then as an isotope will be formed by varying in the number of neutrons for the elements in periodic table. So from the number of protons we can confirm the atomic number of the element. As the atomic number is given as number of protons in case of oxidized element, the atomic number of 26 in the present case will be related to Fe element in the periodic table.
Hence the isotope will be Fe in +2 oxidation state and having the atomic number as 26 and mass number as 26+32 = 58. So there is a change in the mass number of the isotope of Fe from 56 to 58.
Thus, the isotope is identified as 58 Fe²⁺, where 58 is the mass number of the isotope.
