Answer:
The average atomic mass is closer to Si- 28 because this isotope is present in more percentage in the sample.
Explanation:
Given data:
Atomic mass of silicon= ?
Percent abundance of Si-28 = 92.21%
Atomic mass of Si-28 = 27.98 amu
Percent abundance of Si-29 = 4.70%
Atomic mass of Si-29 = 28.98 amu
Percent abundance of Si-30 = 3.09%
Atomic mass of Si-30 = 29.97 amu
Solution:
Average atomic mass = (abundance of 1st isotope × its atomic mass) +(abundance of 2nd isotope × its atomic mass)+(abundance of 2nd isotope × its atomic mass) / 100
Average atomic mass = (92.21×27.98)+(4.70×28.98)+(3.09×29.97) /100
Average atomic mass = 2580.04 +136.21+92.61 / 100
Average atomic mass = 2808.86 / 100
Average atomic mass = 28.08amu.
The average atomic mass is closer to Si- 28 because this isotope is present in more percentage in the sample.
The wavelengths of light that an atom gives off when an electron falls to a lower energy level corresponds to Emission spectrum , Option D is the correct answer.
<h3>What is Emission Spectrum ?</h3>
Light is absorbed or emitted when an electron jumps or falls into an energy level.
The energy of light absorbed or emitted is equal to the difference between the energy of the orbits.
Therefore , the wavelengths of light that an atom gives off when an electron falls to a lower energy level corresponds to Emission spectrum.
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Answer:
4.21
Explanation:
use Avogadro's number
6.023 x 10^23
multiply this by 7 because you want to find 7 moles :
6.023 x 10^23 x 7 = 4.21
I believes you would use grams to describe the mass of a tablespoon an you should report that guy
Explanation:
The periodic table is a table that arranges elements based on their atomic numbers into groups and periods.
The groups are the vertical arrangement of elements. All elements in a group share similar chemical properties because they have the same number of elements in their valence shell. The periodic table groups are:
Group Other names
1A or 1 Alkali metals
IIA or 2 Alkaline earth metals
IIIA or 3 Boron family
VIA or 6 Chalcogens
VIIA or 17 Halogens
O-18 Inert elements
IIIB-IIB Transition elements
There are 18 vertical columns divided into 8 tall groups or main groups which are 1A to O. The short groups or subgroups are from numerals 1B to VIII.
The periodic table can be divided into four blocks based on the type of sublevels their valence electrons occupy.
- Group IA and IIA constitute the s-block
- Group IIIA to O constitute the p-block
- The transition elements makes up the d-block
- The lanthanides and actinides makes up the f-block
Learn more:
Periodic table brainly.com/question/2014634
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