Electrons in an atom can be classified as core electrons and valence electrons. Valence electrons are those electrons which are present in valence shell and participates in bond formation. While, Core electrons are all remaining electrons which are not present in valence shell, hence not take part in bonding.
Atomic number of Selenium (Se) is 34 hence it has 34 electrons with following electronic configuration;
1s², 2s², 2p⁶, 3s², 3p⁶, 4s², 3d¹⁰, 4p⁴
From electronic configuration it is found that the valence shell is 4, and the number of electrons present in valence shell are 6. So,
Core Electrons = Total Electrons - Valence Electrons
Core Electrons = 34 - 6
Core Electrons = 28
Result:
There are 28 core electrons in Selenium.
Answer:
4. -ol
5. cyclic ketone
Explanation:
biology stuff
sorry it's hard to explain
C. Represents an oxidation-reduction reaction
Answer:
C.
Explanation:
The Clean Air Act was enacted in 1973 and brought to action in 1990. The act was passed to supervise air emissions to ensure clean air and atmosphere for people. The act was passed in the wake of premature deaths of hundred of thousands people. The act works with NAAQS to ensure safe and clean air for the safety of public health.
<u>From the given options the correct one is C. The Clean Air Act supervises the activities which emits air and any activities that is found to pollute the air will be labelled as illegal</u>.
Therefore, option C is correct.
Answer:
the answer to number 9 is A.
Explanation:
