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Ronch [10]
4 years ago
11

Mendeleev placed thallium (Tl) in the same group as lithium (Li), sodium (Na), potassium (K), rubidium (Rb), and cesium (Cs). Ho

wever, the modern periodic table doesn’t place thallium in this group. Use the periodic table to find the properties of thallium. Explain why Mendeleev might have grouped thallium in the same group as lithium and sodium. Also explain how thallium is different from the other five elements.
Chemistry
1 answer:
IceJOKER [234]4 years ago
4 0

Answer:

Mendeleev placed thallium (Tl) in the same group as lithium (Li), sodium (Na), potassium (K), rubidium (Rb), and cesium (Cs)

Explanation:

Properties of Thallium :

Thallium is a heavy metal denoted by symbol Tl. It is placed in 13th group and 6th period of modern periodic table. It is very soft in nature. It has 3 valency. It does not occur freely in environment.

Mendeleev  grouped thallium in the same group as lithium and sodium because of he found that as Li, Na etc. have compound with one atom of chlorine(Cl), Thallium(Tl) also forms TlCl. Therefore he placed Tl with these elements.

Thallium is different from the other five elements

Tl has 3 valency whereas lithium (Li), sodium (Na), potassium (K), rubidium (Rb), and cesium (Cs) has only 1 valency.

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When atoms combine they form<br> A. molecules<br> B.periodic table<br> C.particles<br> D.protons
IceJOKER [234]

Answer

A. molecules

Explanation

When atoms or elements combine, they are called molecules. When molecules combine they form compounds.

6 0
4 years ago
To three significant digit,what is the mass percentage of iron in the compound Fe2O3​
svlad2 [7]

69.9%

Explanation:

To find the mass percentage of iron in the compound in Fe₂O₃, we would go ahead to express the given molar mass of the iron to that of the compound.

 Mass percentage  = \frac{molar mass of Fe}{Molar mass of Fe_{2}O_{3}  }  x 100

Molar mass of Fe = 55.85g/mol

Molar mass of O = 16g/mol

Molar mass of Fe₂O₃ = 2(55.85) + 3(16) = 159.7‬g/mol

Mass percentage  = \frac{2(55.85)}{159.7}  x  100   = 69.94% = 69.9%

learn more:

Mass percentage brainly.com/question/8170905

#learnwithBrainly

4 0
3 years ago
How many moles of water are produced from 373 mol Al??
stepladder [879]
I cannot come up with a reaction which you can convert directly from Al to H2O.

But you can convert from Al2O3 to H2O by adding HCL solvent.
5 0
3 years ago
Read 2 more answers
Methylcyclopentene reacting with reacting with sulfuric acid and water
dlinn [17]

Answer:

The product is 1-methylcyclopentanol  

Explanation:

The acid-catalyzed hydration of alkenes involves the addition of a water molecule to a C=C double bond.

H₂O + C=C ⟶ H-C-C-OH

An H atom adds to one of the C atoms, and an OH group adds to the other

This reaction follows Markovnikov’s rule — the H adds to the C atom that has more hydrogen atoms, and the OH adds to the more substituted carbon.

The steps of the mechanism are:

  1. The aqueous sulfuric acid generates hydronium ions
  2. The nucleophilic π electrons attack an H atom  on the hydronium ion, forming a carbocation on the more substituted C atom.
  3. The lone pair electrons on a water molecule attack the carbocation , forming an oxonium ion.
  4. Another water molecule removes the extra proton.

The product is the alcohol with the OH group on the more substituted carbon — 1-methylcyclopentanol.

7 0
4 years ago
What is the electron configuration for helium (He)?<br> 1s1<br> 1s2<br> 1s22s1<br> 1s22s2
sdas [7]

Answer:

your answer will be option B hope ur help and mark me brainlist

8 0
3 years ago
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