Answer:
ecosystem
Explanation:
your welcome hope I helped
Answer:
4 energy levels/rings
Explanation:
By the atomic model proposed by Niels Bohr, the electrons orbit around the nucleus in shells having different energy level each with the ability to contain a given maximum amount of electrons.
The closest shell to the nucleus named the K shell, can have a maximum of two electrons, the next shell known as the L shell can have 8 electrons while the next shell, M, can have a maximum of 18 electrons
The arrangement of the periodic table is based on the number and location of electrons such that elements in the 4th row (period 4 elements) have three completed energy levels/rings before, their valence ring making the total number of rings = 4 energy levels/rings.
Answer:
0.056moles HF and 0.70M
Explanation:
When a strong acid is added to a buffer, the acid reacts with the conjugate base.
In the system, NaF and HF, weak acid is HF and conjugate base is NaF. The reaction of NaF with HCl (Strong acid) is:
NaF + HCl → HF + NaCl
Initial moles of NaF and HF in 60.0mL of solution are:
NaF:
0.0600L × (0.80mol / L)= 0.048 moles NaF
HF:
0.0600L × (0.80mol / L)= 0.048 moles HF
Then, the added moles of HCl are:
0.0200L × (0.40mol / L) = 0.008 moles HCl.
Thus, after the reaction, moles of HF produced are 0.008 moles + the initial 0.048moles of HF, moles of HF are:
<em>0.056moles HF</em>
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In 20.0mL + 60.0mL = 80.0mL = 0.0800L, molarity of HF is:
0.056mol HF / 0.0800L = <em>0.70M</em>
Unless you made a typo. D would be most accurate as it goes the furthest into the decimals
Answer: nS²
Answer: According to the periodic law, elements that fall into the same group have similar properties.
All the alkaline earth metals are in group two of the periodic table. The have 2 electrons in their outermost shell. In the SPDF electronic configuration the ground state of all alkaline earth have S² two electrons in their outermost S sublevel.
Example the electronic configuration of some alkaline earth metals are
Beryllium [He] 2S²
Magnesium is [Ne] 3S² and
Calcium is [Ar] 4S²
the general electronic configuration for alkaline earth metals is nS²