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2 years ago

Composition of the nuclei of two atomic species A and B are given below:

Chemistry

1 answer:

Inessa [10]2 years ago

5 0

Explanation:

(a) mass number = atomic number + number of neutrons

(the atomic number is the number of protons of an element)

mass number of A = 11 + 12 = 23

mass number of B = 17 + 18 = 35

(b) +1 and -1, respectively

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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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6 0

2 years ago

The electronic configuration of an element is given below.

Shalnov [3]

Answer:

It is reactive because it has to gain an electron to have a full outermost energy level.

Explanation:

The electron configuration of oxygen is 1s2,2s2 2p4.

Oxygen is in group six in the periodic table so it has six electrons in its valence shell. This means that it needs to gain two electrons to obey the octet rule and have a full outer shell of electrons (eight).

3 0

2 years ago

Which part of the periodic would contain an element with a partially filled f sublevel

noname [10]

Answer: Lanthanide and actinide series

Explanation: The elements with partially or fully filled f orbitals belong to f block elements.

f block elements include lanthanides and actinides. They are called so the lanthanides contain the first element named as lanthanum and actinides contain first element named as actinium. They are also called as inner transition elements.

All of them have general electronic configuration:

$(n-2)f^{1-14}(n-1)d^{0-10}ns^2$ , where n = 6-7

8 0

2 years ago

Read 2 more answers

P4O10 -> 4P+5O2 How many moles of phosphorus would be produced if 5.3 mol of P4O10 reacted?

viktelen [127]

Answer:

21.2 moles.

Explanation:

Hello!

In this case, for the given chemical reaction, we can see there is a 1:4 mole ratio between tetraphosphorous decaoxide and phosphorous; therefore, the following proportional factor provides the requested moles of phodphorous:

$n_P=5.3molP_4O_{10} *\frac{4molP}{1molP_4O_{10}} \\\\n_P=21.2molP$