Answer:
The elements in the alkaline earth metals group; beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), and radium (Ra), have two electrons in their outer electronic shell.
Explanation:
ELECTRON CONFIGURATION
Highest occupied energy level of an element
equal to the period
for example, the highest occupied energy level of He is 1, Be is 2, Al is 3, Ca is 4, and Sn is 5
<u>Answer:</u> The initial concentration of hydrogen peroxide at the given temperature is 0.399 M
<u>Explanation:</u>
Decomposition of hydrogen peroxide is following first order kinetics.
Rate law expression for first order kinetics is given by the equation:
![k=\frac{2.303}{t}\log\frac{[A_o]}{[A]}](https://tex.z-dn.net/?f=k%3D%5Cfrac%7B2.303%7D%7Bt%7D%5Clog%5Cfrac%7B%5BA_o%5D%7D%7B%5BA%5D%7D)
where,
k = rate constant = 
t = time taken for decay process = 855 s
![[A_o]](https://tex.z-dn.net/?f=%5BA_o%5D)
= initial amount of the reactant = ?
[A] = amount left after decay process = 0.321 M
Putting values in above equation, we get:
![2.54\times 10^{-4}s^{-1}=\frac{2.303}{855s}\log \frac{[A_o]}{0.321}](https://tex.z-dn.net/?f=2.54%5Ctimes%2010%5E%7B-4%7Ds%5E%7B-1%7D%3D%5Cfrac%7B2.303%7D%7B855s%7D%5Clog%20%5Cfrac%7B%5BA_o%5D%7D%7B0.321%7D)
![[A_o]=0.399M](https://tex.z-dn.net/?f=%5BA_o%5D%3D0.399M)
Hence, the initial concentration of hydrogen peroxide at the given temperature is 0.399 M
Electron affinity is defined as the change in energy (in kJ/mole) of a neutral atom (in the gaseous phase) when an electron is added to the atom to form a negative ion. In other words, the neutral atom's likelihood of gaining an electron.
Electron Affinity of Lithium is 59.6 kJ/mol.
Electron Affinity of Caesium is 45.5 kJ/mol.
Electron Affinity of Lithium is 59.6 kJ/mol. Electronegativity of Lithium is 0.98. ... Electron affinities are more difficult to measure than ionization energies. An atom of Lithium in the gas phase, for example, gives off energy when it gains an electron to form an ion of Lithium.
Trends
The ionization energy of the elements within a period generally increases from left to right. This is due to valence shell stability.
The ionization energy of the elements within a group generally decreases from top to bottom. This is due to electron shielding.
The noble gases possess very high ionisation energies because of their full valence shells as indicated in the graph. Note that helium has the highest ionization energy of all the elements.
Answer:
In simple words, in an open system, the system that has external interactions. Such interactions can take the form of information, energy, mass etc. So keeping this definition in mind, the law of conservation of mass in open system is difficult because when chemical reaction takes places things change form and some things are released as energy, That energy than escapes the system and interacts with other surrounding. This is why it is difficult to demonstrate Law of Conservation of Mass because the changes in mass due to chemical reaction cannot be accounted for properly since the lost mass (in form of energy) was lost to environment.
Whereas, in closed system, all components occur inside a closed container or something where external interactions are minimal to none so the energy lost due to chemical reaction does not escape the system thus it can be accounted for properly to demonstrate the law of conservation of Mass.
Explanation:
Too many words but should get the point across hopefully!
