Answer:
Explanation:
The following are the order of point from oldest to most recent
1. Atoms are tiny indivisible particles that make up all mater.
it is Postulate of Dalton's atomic theory. this theory was put forward in 1803
2. Negatively charged electrons are embedded in a mass of positive charge.
In 1897 J.J Thomson discovered that atom consist of tiny negatively charged particles called electrons that are uniformly spread in +vely charged matrix this model called as plum pudding model.
3. Atoms consist of mostly empty space with a dense nucleus of positive charge.
While doing experiment on gold foil Rutherford presented a model in 1909 and stated that atom consist mostly empty space with dense nucleus.
4. Electrons occupy specific energy levels surrounding a positively charged nucleus.
Niels Bohr in 1913 put forward a model to explain atomic orbitals/energy level. This is a postulate of Bohr model.
5. Electrons move about a positively charged nucleus in clouds that are defined by probabilities.
In 1926 Erwin Schrödinger explain the wave function of electrons and its probability.
Answer:
18 DAYS IS THE HALF LIFE OF THE RADIOISOTOPE.
Explanation:
Using the formula
Nt = No * (1/2)^t/t1/2
where;
Nt = amount remaining = 25 g
No = Initial amounrt of the radioisotope = 50 g
t = time elapsed = 18 days
t1/2 = half life = unknown
Substitute the values into the equation and obtain the half life of the radioisotope;
Nt = No * (1/2) ^t/t1/2
25 = 50 * (1/2) ^18/t1/2
25 /50 = (1/2)^18/ t1/2
1/2 = (1/2)^18/t1/2
1/2)^1 = (1/2)^18/t1/2
1 = 18/t1/2
t1/2 = 18 days.
So therefore the half life of the radioisotope is 18 days.
The hybridization for the Br in BrO4⁻ is
. So, the correct option is (e).
In chemistry, the idea of combining atomic orbitals to create new hybrid orbitals (with different energies, shapes, etc., than the component atomic orbitals) is known as orbital hybridisation (or hybridization). These new hybrid orbitals are suitable for the pairing of electrons to form chemical bonds in valence bond theory.
Because more directional hybridised orbitals result in higher overlap when creating bonds, stronger bonds are formed, which favours the hybridization of orbitals. When hybridization takes place, this leads to more stable molecules.
One s orbital and three p orbitals combine to form four
orbitals, each of which has a 25% s character and a 75% p character. This process is known as
hybridization. Anytime an atom is surrounded by four groups of electrons, this kind of hybridization is necessary.
Learn more about hybridization here:
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The number of atoms in one mole is same in both which is 6 x 10^23 ^23 means power 23