Based on atomic mass
Explanation:
Elements were arranged on the first periodic table based on their atomic masses.
The mass of an atom is made up of the mass of the nucleus which contains the protons and neutrons.
- Dimitri Mendeleev was the first person credited for arranging elements periodically.
- He was said to have been inspired while playing his game of solitaire on a train.
- On his table, he left spaces for the atomic masses of elements not yet discovered.
- Today, the periodic table is based on the atomic numbers of elements. This is the number of protons in an atom.
Learn more:
Periodic table brainly.com/question/2690837
#learnwithBrainly
More reactive than others
Let's eliminate these one by one.
The first pair would not be the same, as X would most likely be in group IA, and Y would be in group VIIA, because of their tendency to gain and lose electrons.
The second pair would also violate the same rule, but X would most likely be in group IIA, and Y would most likely be in group VIA.
The third pair would not be the same, as X is most likely in group VIIA, and since Y has eight valence electrons, it is most likely a noble gas.
The final pair has X with atomic number 15, making it phosphorous. Phosphorous wants to gain 3 electrons to have a full octet of 8 outer "valence" electrons, and Y would also like to gain 3 electrons. This means it is possible that the final pair would be in the same group.
Answer: 72.93 litres
Explanation:
Given that:
Volume of gas (V) = ?
Temperature (T) = 24.0°C
Convert 24.0°C to Kelvin by adding 273
(24.0°C + 273 = 297K)
Pressure (P) = 1.003 atm
Number of moles (n) = 3 moles
Molar gas constant (R) is a constant with a value of 0.0821 atm L K-1 mol-1
Then, apply ideal gas equation
pV = nRT
1.003 atm x V = 3.00 moles x 0.0821 atm L K-1 mol-1 x 297K
1.003 atm•V = 73.15 atm•L
Divide both sides by 1.003 atm
1.003 atm•V/1.003 atm = 73.15 atm•L/1.003 atm
V = 72.93 L
Thus, the volume of the gas is 72.93 litres
1) Chemical reactions produce new substances
Ans (d)
2) The symbol, Δ in a chemical reaction means that heat of supplied to the reaction.
Ans (a)
3) A skeleton equations does not show the reaction stoichiometry, i.e. the relative amounts of reactants and products.
Ans (d)
