The simple trick which one can consider in such problem where it is asked for positron emission is :
<span>When the atomic number goes DOWN by one and mass number remains unchanged, then a positron is emitted.
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<span>a. </span>
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Here the atomic number decreases by one.
Similarly, options b and d are eliminated.
Option c is also not the answer.
For c, Count the atomic number on left side and compare it with right side. You will see it is 9 on left and 8 on right. Atomic no. did go down by 1. But the atomic mass is changed as well.
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This has only only three sig figs because it is 546.000 the zeros are just place holders so thus meaning they are not significant. It is just another way to write 546 because in that number there is also 3 sig figs. They are just trying to throw you off. Just watch out because if the example is 540 then it is just two significant digits, and it were to be 540. then it be three cause that "." makes the zero significant. <span />
<em>I am going to use first-person pronouns for this drop of water</em>
[ Start ] Liquid
I start out as a drop of water among other drops of water in the ocean. I am currently a liquid as I can change shape easily but I do not float up.
[ Middle ] Gas
The sun feels very hot. From the heat I turn into a gas, specifically water vapor, and float up into the sky.
[ Middle x 2 ] Solid
In the sky I meet up with a lot of my past friends. We form a cloud, and as we grow heavier (the more the merrier) we start to fall down. It is extremely cold now, so we fall down as a solid, also known as hail or snow.
[ End ] Liquid
We hit the ocean again as we fall from the sky. I'm so happy to be back home as a water drop again!
Have a nice day! - <u>Please note this is very simplified</u>
I hope this is what you are looking for, but if not - comment! I will edit and update my answer accordingly. (ノ^∇^)
- Heather
Explanation:
Bases have a slippery feel when touched but acids do not have a slippery feel.
- An acid is a substance that interacts with water to produce excess hydroxonium ions, H₃O⁺ in an aqueous solution. Here are some of its properties:
- Their dilute solutions have a sour taste.
- They have a burning effect on the skin and are highly corrosive on metals.
- They have the ability to change the colors of indicators.
- They react with bases to form salt and water only.
Examples of acids are:
Hydrochloric acid HCl
Tetraoxosulphate (VI ) acid H₂SO₄
- A base is a substance that interacts with water to produce excess hydroxide ions, OH⁻ in an aqueous solution.
- They typically have a bitter taste.
- They have a soapy feel
- They are electrolytes
- They also change the color of indicators
Examples are:
Potassium hydroxide KOH
Sodium hydroxide NaOH
Learn more:
Neutralization brainly.com/question/6447527
#learnwithBrainly
Answer:
The answer is: the number of unpaired valence electrons
Explanation:
The valence electrons are the number of electrons present in outer shell of an atom that participate in chemical bond formation, if the outer shell is not completely filled.
Covalent bond formation occurs when two atoms contribute one valence electron each to form a bond. Thus the number of covalent bonds that an element can form, can be determined by the number of unpaired valence electrons.
Therefore, the nature and the number of bonds formed by the element and the chemical properties of the element can be determined by the number of valence electrons present in the outer shell of the element.
