Answer:
B.) An atom of arsenic has one more valence electron and more electron shells than an atom of silicon, so the conductivity decreases because the arsenic atom loses the electron.
Explanation:
Silicon is located in the 3rd row and 14th column in the periodic table. Arsenic is located in the 4th row and 15th column in the periodic table. This means that arsenic has one more valence electron than silicon. Since arsenic is located one row down from silicon, its valence electrons occupy higher energy orbitals.
Silicon maintains a crystal-like lattice structure. Each silicon atom is covalently connected to assume this shape. When silicon gains one extra electron from arsenic, it experiences n-type doping. This new electron is not tightly bound in the lattice structure. This allows it to move more freely and conduct more electricity. This can also be explained using band gaps. Silicon, which previously had an empty conduction band, now has one electron in this band. This lowers the band gap between the conduction and valence bands and increases conductivity.
First, isotopes <u>are the atoms of a single element whose nuclei have a different number of neutrons</u>, and therefore, differ in mass numbers. You should know that atoms are formed by a nucleus that has a small size and is made up of protons and neutrons. The nucleus is surrounded by a cloud of electrons, which are found in a region of the atom called the cortex.
The mass number, represented as A, <u>is the sum of the number of protons and neutrons in the nucleus</u>. On the other hand, the atomic number (Z) is <u>the number of protons that exist in the nucleus.
</u>
The isotopes of an element X are represented as follows,
<em>(see first attached picture)</em>
It should be noted that the number of neutrons of a chemical element can be calculated as the difference A-Z.
<u>The atomic and mass numbers of bismuth with 125 neutrons are</u>:
Z = 83
A = 83 + 125 = 208
Thus, the atomic symbol of the bismuth isotope with 125 neutrons is:
<em>(see second attached picture)</em>
The correct answer would be 3.) Location of an electron
Answer:
The concentration of acetic acid is 8.36 M
Explanation:
Step 1: Data given
Volume of acetic acid = 1.00 mL = 0.001 L
Volume of NaOH = 32.40 mL = 0.03240 L
Molarity of NaOH = 0.258 M
Step 2: The balanced equation
CH3COOH + NaOH → CH3COONa + H2O
Step 3: Calculate the concentration of the acetic acid
b*Ca*Va = a*Cb*Vb
⇒with b = the coefficient of NaOH = 1
⇒with Ca = the concentration of CH3COOH = TO BE DETERMINED
⇒with Va = the volume of CH3COOH = 1.00 mL = 0.001L
⇒with a = the coefficient of CH3COOH = 1
⇒with Cb = the concentration of NaOH = 0.258 M
⇒with Vb = the volume of NaOH = 32.40 mL = 0.03240 L
Ca * 0.001 L = 0.258 * 0.03240
Ca = 8.36 M
The concentration of acetic acid is 8.36 M
