Answer:
1. solid and liquid
2.Evaporation changes liquid water to water vapour.
On earth, oxygen is the most common element, making up about 47% of the earth's mass. Silicon is second, making up 28%, followed by aluminum (8%), iron (5%), magnesium (2%), calcium (4%), sodium (3%), and potassium (3%). All of the remaining elements together make up less than 1% of the earth's mass.
Answer:
Linear combination of atomic orbitals (LCAO) is a simple method of quantum chemistry that yields a qualitative picture of the molecular orbitals (MOs) in a molecule. Let us consider H
+
2
again. The approximation embodied in the LCAO approach is based on the notion that when the two protons are very far apart, the electron in its ground state will be a 1s orbital of one of the protons. Of course, we do not know which one, so we end up with a Schrödinger cat-like state in which it has some probability to be on one or the other.
As with the HF method, we propose a guess of the true wave function for the electron
ψg(r)=CAψ
A
1s
(r)+CBψ
B
1s
(r)
where ψ
A
1s
(r)=ψ1s(r−RA) is a 1s hydrogen orbital centered on proton A and ψ
B
1s
(r)=ψ1s(r−RB) is a 1s hydrogen orbital centered on proton B. Recall ψ1s(r)=ψ100(r,ϕ,θ). The positions RA and RB are given simply by the vectors
RA=(0,0,R/2)RB=(0,0,−R/2)
The explicit forms of ψ
A
1s
(r) and ψ
B
1s
(r) are
ψ
A
1s
(r) =
1
(πa
3
0
)1/2
e−|r−RA|/a0 ψ
B
1s
(r) =
1
(πa
3
0
)1/2
e−|r−RB|/a0
Now, unlike the HF approach, in which we try to optimize the shape of the orbitals themselves, in the LCAO approach, the shape of the ψ1s orbital is already given. What we try to optimize here are the coefficients CA and CB that determine the amplitude for the electron to be found on proton A or proton B.
Explanation:
Answer:
All atoms of the same element have always have the same amount of protons.
Explanation:
Atoms of the same element have always have the same amount of protons but not always the same electrons and neutrons. If an atom gains or loses one of its valance electrons, the electrons on the outermost shell, then it becomes ionized. Also not all atoms of the same element have the same amount of neutron. This is called an isotope. A good example would be Carbon 13. Normally, Carbon atoms have an atomic mass of 12 AMU or 12 atomic mass units. However, Carbon atoms have an atomic mass of 13 AMU, consisting of 7 neutrons instead of 6 neutrons. So the only thing that all atoms of the same element have in common is the amount of protons.