Answer:
The possible valances can be determined by electron configuration and electron negativity
Good Luck even though this was asked 2 weeks ago
Explanation:
All atoms strive for stability. The optima electron configuration is the electron configuration of the VIII A family or inert gases.
Look at the electron configuration of the nonmetal and how many more electrons the nonmetal needs to achieve the stable electron configuration of the inert gases. Non metals tend to be negative in nature and gain electrons. ( They are oxidizing agents)
For example Florine atomic number 9 needs one more electron to reach a valance number of 8 electrons to equal Neon atomic number 10. Hence Flowrine has a valance of -1
Oxygen atomic number 8 needs two more electrons to reach a valance number of 8 electrons to equal Neon atomic number 10. Hence Oxygen has a valance charge of -2.
Non metals with a low electron negativity will lose electrons when reacting with another non metal that has a higher electron negativity. When the non metal forms an ion it is necessary to look at the electron structure to determine how many electrons the element can lose to gain stability.
For example Chlorine which is normally -1 like Florine when it combines with oxygen can be +1, +3, + 5 or +7. It can lose its one unpaired electron, or combinations of the unpaired electron and sets of the three pairs of electrons.
An exponential decay law has the general form: A = Ao * e ^ (-kt) =>
A/Ao = e^(-kt)
Half-life time => A/Ao = 1/2, and t = 4.5 min
=> 1/2 = e^(-k*4.5) => ln(2) = 4.5k => k = ln(2) / 4.5 ≈ 0.154
Now replace the value of k, Ao = 28g and t = 7 min to find how many grams of Thalium-207 will remain:
A = Ao e ^ (-kt) = 28 g * e ^( -0.154 * 7) = 9.5 g
Answer 9.5 g.
I don’t know if I am right but I think it is symbol for the first one and the second one is formula.
Answer:
It looks alittle dark can you fix it?
Answer:
Ag
Explanation:
To determine which element will displace hydrogen from a dilute acid, we need to make reference to the activity series or the electrochemical series. The activity series is a list of metallic ions according to their electropositivity.
This means elements are ranked here based on how electrically positive they are. Hence, an element above another element is relatively more electropositive than the one under it. For example calcium is less electropositive compared to sodium as calcium is found under sodium in the list.
Now, for an element to displace hydrogen, it means the particular element is more electropositive than hydrogen on the activity series. All the elements in the options are in a greater position relative to hydrogen on the activity series except silver. This means it cannot displace hydrogen from a dilute mineral acid
