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2 years ago

Please help me I don’t understand this !!!

Chemistry

1 answer:

alexira [117]2 years ago

3 0

Answer:

The real answer for a is-He(helium)4,002602

The answer for b is-Mg(Magnesium) 24.305

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What is the molecular formula of first 20 elements

attashe74 [19]

Answer:

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3 years ago

Why gold is called inert metal

astraxan [27]

Gold has a heavy enough nucleus that its electrons must travel at speeds nearing the speed of light to prevent them from falling into the nucleus. This relativistic effect applies to those orbitals that have appreciable density at the nucleus, such as s and p orbitals. These relativistic electrons gain mass and as a consequence, their orbits contract. As these s and (to some degree) p orbits are contracted, the other electrons in d and f orbitals are better screened from the nucleus and their orbitals actually expand.

Since the 6s orbital with one electron is contracted, this electron is more tightly bound to the nucleus and less available for bonding with other atoms. The 4f and 5d orbitals expand, but can't be involved in bond formation since they are completely filled. This is why gold is relatively unreactive.

Hope it helps

5 0

2 years ago

Extend your thinking: The slow decay of radioactive materials can be used to find the age of rocks, fossils, and archaeological

lisov135 [29]

The age in years of the Egyptian papyrus, the Aboriginal charcoal, the Mayan headdress, and the Neanderthal skull are 4000 years, 13106.5years , 2040 years, and 30353 years respectively.

<h3>What is the half-life of a radioactive material?</h3>

The half-life of a radioactive material is the time taken for half the atoms present in the material to decay or disintegrate.

The half-life, $t_\frac{1}{2}$ , the age, t, and amount remaining, $A_{r}$ , of a radioactive material are related by the formula below:

$t = \frac{t_\frac{1}{2}*A_{r}}{-ln2}$

Half-life of carbon-14 = 6000 years

For the Egyptian papyrus with 63% of its original carbon-14 atoms: $t = \frac{6000*0.63}{-0.63} = 4000\:years$

For the Aboriginal charcoal with 22% of its original carbon-14 atoms:

$t = \frac{6000*0.22}{-0.63} = 13106.5\:years$

For the Mayan headdress with 79% of its original carbon-14 atoms:

$t = \frac{6000*0.79}{-0.63} = 2040\:years$

Neanderthal skull with 3% of its original carbon-14 atoms:

$t = \frac{6000*0.03}{-0.63} = 30353\:years$

Therefore, the age in years of the Egyptian papyrus, the Aboriginal charcoal, the Mayan headdress, and the Neanderthal skull are 4000 years, 13106.5years , 2040 years, and 30353 years respectively.

Learn more about half-life at: brainly.com/question/26689704

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2 years ago

Which substance can not be decomposed by a chemical change?<br> (1) AlCl3 (3) HI<br> (2) H2O (4) Cu

user100 [1]

Cooper is the substance that can't be decomposed by a chemical chAnge. So 4)

5 0

3 years ago

Read 2 more answers

True or false. Large covalent molecules with the same molecular formula or more likely to have identical angles between orbitals

Alexeev081 [22]