Answer:
The percentage of the block contains 15% after 60 years.
Explanation:
Step 1: Formula for half-life time
To calculate the half-life time we will use the following formula:
At = A0 * 1/2 ^(x/t)
With At = the quantity after a time t
A0 = The quantity at time t = 0 (start)
x = time in this case = 60 years
t= half-life time = 22 years
Step 2: Calculate the percentage after 60 years
In this case: after 60 years the percentage will be
A0= 10 * 1/2 ^(60/22)
A0 = 1.5
A0 / At = 1.5 /10 = 0.15
0.15 *100% = 15 %
The percentage of the block contains 15% after 60 years.
The most reactive metal<span> in the periodic table (Cesium) with the most reactive non-</span>metal<span> (</span>Fluorine<span>).</span>
Answer:
1.204 × 10²³
Explanation:
The number of atoms in a mole is always 6.022 × 10²³, known as Avogadro's number or Avogadro's constant.
To convert moles to atoms, multiply the molar amount by Avogadro's number.
(6.022 × 10²³) × 0.2
= 1.204 × 10²³
The magnitude of dispersion forces in Br2 is greater than the magnitude of dispersion forces in Cl2.
Atomic radius decreases across the period but increases down the group. As more shells are added to the atom, the repulsion between electrons increases. Across the group, more electrons are added without increase in the number of shell hence atomic radius decreases across the period due to increase in the size of the nuclear charge. Therefore, the atomic radius of Li is larger than that of Be.
Ionization energy is a periodic trend that increases across the period but decreases down the group. Since the outermost electron is further from the nucleus due to screening of inner electrons, ionization energy decreases down the group. Across the period, the size of the nuclear charge increases hence ionization energy increases across the period.
For K, the second electron is removed from an inner shell which requires a very large amount of energy. In Ca, the second electron is removed from the valence shell which requires a lesser amount of energy. Therefore, the second ionization energy of K is greater than the second ionization energy of Ca.
The carbon to carbon bond in C2H4 is a double bond which has a greater bond enthalpy than the single bond in C2H6. As such, the carbon to carbon bond in C2H4 has a greater bond energy than the carbon to carbon bond in C2H6.
The boiling point of Cl2 is lower than the boiling point of Br2 because Br2 is larger than Cl2 hence the magnitude of dispersion forces in Br2 is greater than the magnitude of dispersion forces in Cl2.
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