Answer:
Have the same number of electrons in their outer energy levels
Explanation:
Elements in the same group have similar chemical properties because they have the same number of valence electron(s) in their outermost shell.
Chlorine and Iodine have similar chemical properties because they have the same number of valence electron in their outermost shell. This can be seen from their electronic configuration as shown below:
Cl (17) => 1s² 2s²2p⁶ 3s²3p⁵
I (53) => [Kr] 4d¹⁰ 5s²5p⁵
From the above illustration:
Outer shell of Cl (3s²3p⁵) = 2 + 5 = 7 electrons
Outer shell of I (5s²5p⁵) = 2 + 5 = 7 electrons
Since they have the same number of valence electrons, therefore, they will have similar chemical properties.
Answer:-
0.91% is the students % of error
Explanation: -
Accepted value= 12.11 grams
Measured value = 12.22 grams
Error = 12.22-12.11 = 0.11 grams
Percentage error = 
x100
= 0.91 %
Thus 0.91% is the students % of error
Answer:
-86.02 kJ/ mole
Explanation:
The moles of the acid used = Molarity × Volume (L) =
= 0.50 (0.0372 L)
= 0.0186 moles
The heat released = -1.6 kJ
∴ 0.0186 moles neutralization of HA heat is: -1.6 kJ
The molar heat of neutralization due to one mole of the unknown acid = -1.6/0.0186
= -86.02 kJ/ mole
Answer: The temperature rise is 
Explanation:
The quantity of heat required to raise the temperature of a substance by one degree Celsius is called the specific heat capacity.
Q = Heat absorbed by ice = 5280 J
m = mass of ice = 2.40 kg = 2400 g (1kg=1000g)
c = heat capacity of water = 
Initial temperature = 
Final temperature = 
Change in temperature ,
Putting in the values, we get:
Thus the temperature rise is
Explanation:
Half life is simply the amount of time it takes for half of a substance to decompose.
Options;
- Carbon-14 has a half-life of 5,730 years. A 30 gram sample will be 10 grams after 5,730 years. This is incorrect. After 5730 years, 15g of the sample ought to remain.
- Nickel-59 has a half-life of 76,000 years. A sample would go through 3 half-lives in 228,000 years. This is correct. 3 * 76000 = 228,000
- Hafnium-182 has a half-life of 9 million years. A 38 gram sample would be 4.75 grams in 27 million years. This is incorrect. Mass after 3 half lives (27/9) = 9.5 (38 / 2 / 2)
- Iron-60 has a half-life of 1.5 million years. In 6 million years a 40 gram sample would be reduced to 10 grams. This is incorrect. Mass after 4 half lives (6 / 1.5) = 2.5 gram (40 / 2 / 2 /2 / 2)
- Lead-202 has a half-life of 52,500 years. The original sample must have been 120 grams if you have a 60 gram sample after 105,000 years. This is incorrect. Original sampe = 240 gram. So after 2 half lives (105,000/52500), mass left = 60 (240 / 2 /2)
