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3 years ago

Why are the elements 57 through 71 and 89 through 102, found separately at the bottom of the table?

1 answer:

8 0

Elements from 57 to 71 are Lanthanoids and from 89 to 103 are Actinoids. Simply I would say Actinoids have less similarity in chemical properties than Lanthanoids. On the other hands, Actinoids have randomized chemical strutural bonds.

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As with any drug, aspirin (acetylsalicylic acid) must remain in the bloodstream long enough to be effective. Assume that the rem

Olenka [21]

Answer:

180 mg

Explanation:

For a first-order reaction, we can calculate the amount of aspirine (A) at a certain time (t) using the following expression.

$A=A_{0}.e^{-k.t}$

where,

k: rate constant

A₀: initial amount

If we know the half-life ( $t_{1/2}$ ) we can calculate the rate constant.

$k=\frac{ln2}{t_{1/2}} =\frac{ln2}{3h} =0.2h^{-1}$

When t = 4 h and A₀ = 400 mg, A is:

$A=400mg.e^{-0.2h^{-1}\times 4h} =180mg$

4 0

3 years ago

Select all that apply.

alexgriva [62]

Hi!

<u>The correct options would be: </u>

is an electron

is emitted from nucleus

has a -1 charge

Explanation:

A beta particle is a result of a neutron (a neutral particle) changing into two particles of opposite charges - a high energy electron (with a negative charge -1) and a positron (with a positive charge +1). Neutrons are present in the nucleus of an atom, and thus the beta particles are said to be emitted from the nucleus. They do have a charge, not zero, but it is not +2 and can only be either -1 or +1. This form of radiation is not electromagnetic energy because beta particles are massless, and do not travel at the speed of light (both being characteristics of electromagnetic radiation). Beta particles are not pure forms of energy.

Hope this helps.

6 0

3 years ago

8. Which of the following is TRUE about limiting and excess reactants?

Ivahew [28]

B. The limiting reactant determines the max amount of product that can be formed

5 0

3 years ago

What is the electronic configuration of Au3+?

Anettt [7]

Answer:

$AU^{3+} : [Rn] 5f^3$

Explanation:

Writing electronic configuration of any element you should know atomic number of that element ,

and also electrons are filling according to their energy level and first electron is filled in the lower energy orbital

and it follows n+1 rule if n+1 is same for two orbital electron will go first in the lowest value of n.

writing electronic configuration of ion can be done like first for their neutral atom and then add or remove electron it will make things easy because there are also some eception case their you may do wrong.

$AU : [Rn] 5f^3 6d^1 7s^2$

remove three electron from outer most shell of AU

$AU^{3+} : [Rn] 5f^3$

4 0

3 years ago

PLEASE HELP THANKS:))))))

weeeeeb [17]

Explanation:

-plants that can absorb copper ions are grown on soil with low grade copper ores.

-the plants are burned and the copper compounds are within the Ash.

-copper ions can be leached from the Ash by adding sulphuric acid, this makes a solution of copper sulphate

-the displacement of scrap iron makes pure copper metals.

3 0

3 years ago