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geniusboy [140]
2 years ago
8

A radioactive substance has a half-life of 5 million years. What is the age of a rock in which 25% of the original radioactive a

toms remain? You must show your work or explain how you came up with your answer for full credit.
Chemistry
1 answer:
GenaCL600 [577]2 years ago
5 0

Answer:

10 million years

Explanation:

For a sample to decay to 25% of its original amount, 2 half lives must have passed. Since one half life is 5 million years, multiplying this by 2 gives us that 2 half lives is 10 million years.

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Which of these characteristics do these elements have in common?
Over [174]

C) They each form similar compounds when combined with oxygen.

Explanation:

The given elements have a common characteristics as they each form similar compounds when combined with oxygen.

Beryllium, magnesium and calcium all are located in the alkaline earth group.

Elements in the same group have the same chemical properties.

  • Density and melting point are physical properties of matter which varies down a group on the periodic table.
  • Their reaction with oxygen denotes a statement of their chemical properties.
  • Chemical properties of matter is a function of their valency.
  • Group two elements have a valency of two. They have two electrons in their outermost shell.
  • Therefore, they all form ionic bonds when they react with oxygen.

learn more:

Periodic table brainly.com/question/2690837

#learnwithBrainly

6 0
3 years ago
Define saturated and unsaturated fats​
Sphinxa [80]

Answer:

<h3><u>Saturated and unsaturated</u>:-</h3>

Are a form of fat in which all or most of the fatty acid chains are single bonds. Glycerol and fatty acids are the two types of smaller molecules that make up fat.

<h3><u>Saturated fat is found in:</u></h3>
  • cakes
  • sausages
  • cheese
  • butter
<h3><u>Examples of unsaturated fats:- </u></h3>
  • Olive
  • Nuts(almonds, hazelnuts)
  • Seeds(pumpkin and sesame seeds)

hope it helps...

6 0
3 years ago
Put the following elements into five pairs of elements that have similar chemical reactivity: F, Sr, P, Ca, O, Br, Rb, Sb, Li, S
kirill115 [55]

Explanation:

Given elements:

  F, Sr, P, Ca, O, Br, Rb, Sb, Li, S

Elements with the same chemical reactivity will belong to the same group on the periodic table. This implies that elements in the same column will have the same reactivity;

  Li and Rb are both alkali metals in group 1

  Ca and Sr are both alkali earth metals in group 2

  F and Br are halogens in group 7

  O and S are group 6 elements

 P and Sb are both in group 5 on the periodic table

So these groupings show elements with the same chemical properties.

7 0
2 years ago
How did Bohr refine the model of the atom? How did Bohr refine the model of the atom? He developed electrochemistry. He discover
BartSMP [9]

Answer:

He developed the concept of concentric electron energy levels

Explanation:

Before Bohr's model, Rutherford's model was proposed. This model explains most of the properties of the atom but failed to explain the stability of the atom.

As per Rutherford's model, electrons revolve around the nucleus in the orbit.

But revolving electron in their orbit around nucleus would give up energy and so gradually move towards the nucleus and therefore, eventually collapse.

Bohr's proposed that the electrons around the nucleus move orbit of fixed energy called "stationary states". Electrons in these stationary states  do not radiate energy.

Therefore, proposal of concentric electron energy levels refine the atomic models.

5 0
3 years ago
When objects touch each other, charge can be transferred by
Dovator [93]

Answer:

friction

Explanation:

electrons from one uncharged object to another uncharged object by rubbing. When two uncharged objects rub together, some electrons from one object can move onto the other object. hope this is your right

and not just a riddle

7 0
3 years ago
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