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2 years ago

Periods on the periodic table represent elements ______.

Chemistry

1 answer:

hoa [83]2 years ago

7 0

Answer:

B:with increase in number of valence electrons

Explanation:

As we move from left to right across the periodic table the number of valance electrons in an atom increase. The atomic size tend to decrease in same period of periodic table because the electrons are added with in the same shell. When the electron are added, at the same time protons are also added in the nucleus. The positive charge is going to increase and this charge is greater in effect than the charge of electrons. This effect lead to the greater nuclear attraction. The electrons are pull towards the nucleus and valance shell get closer to the nucleus. As a result of this greater nuclear attraction atomic radius decreases and ionization energy increases because it is very difficult to remove the electron from atom and more energy is required.

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Which of the following is the best piece of laboratory glassware for preparing 500.0 mL of an aqueous solution of a solid?

Leni [432]

Answer:

The correct answer is option A.

Explanation:

Volumetric flask : A glass ware with round lower body with flat bottom and with thin cylindrical neck along with mark which indicates the specific volume filled to that mark.It is used in preparation of standard solution of compound with desired concentration with fixed volume.

Erlenmeyer flask : is a flask with conical shape with flat bottom used in titration experiments to carry out reaction with fixed volume of solution.

Test tube : Small cylindrical tube with rounded bottom used to observe reaction in between reactant taken in small amount.

Graduated beaker : Laboratory glassware used measure larger volumes of solution or to mix or stir solutions and liquids.

Graduated cylinder : Laboratory thin cylindrical glassware with accurate marking of volume used to measure an accurate volume of solutions or liquids required in an experiment.

Volumetric flask is the best piece of laboratory glassware for preparing 500.0 mL of an aqueous solution of a solid

8 0

2 years ago

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A scientist notices that a lump of niobium is warm to the touch and wonders if nuclear reactions are taking place in the metal.

Sedaia [141]

Of the answers listed option B looks like the most complete. Ie "Check for the presence of alpha, beta, and gamma particles." the significant presence of these particles is a specific indicator of radioactive decay, i.e: unstable atoms spontaneously undergoing a nuclear reaction.

6 0

2 years ago

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Which of these statement(s) is/are true about a balloon filled with 1.00 mol N2 (g) at STP?

lara [203]

Answer:

I. The balloon has a volume of 22.4L

III. The balloon contains 6.022x10^23 molecules.

Explanation:

At stp, it has been proven that 1mole of a gas occupy 22.4L.

Therefore, option (i) is correct.

The molar mass N2 = 14.01 x 2 = 28.02g/mol

Number of mole of N2 = 1 mole

Mass of N2 =..?

Mass = mole x molar Mass

Mass of N2 = 1 x 28.02 = 28.02g.

The mass content of the balloon is 28.02g, therefore, option (ii) is wrong.

From Avogadro's hypothesis, we understood that 1 mole of any substance contains 6.02x10^23 molecules. This implies that 1 mole of N2 also contains 6.02x10^23 molecules

Therefore, option (iii) is correct.

The correct options to the question are:

Option i and option iii

7 0

2 years ago

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What type(s) of bonding would be expected for each of the following materials: brass (a copper-zinc alloy), rubber, barium sulfi

mr_godi [17]

The force of attraction that results in holding of atoms or ions together in a molecule or crystal is said be bonding. Bond formation can take place by either attraction or transfer of electrons. There are single, double, and triple bonds. There are many types of bonding namely:

Covalent (sharing of electrons takes place).

Ionic (transfer of electrons takes place).

Metallic (ionized atoms of metals and the sea of electrons around them).

Brass (a copper-zinc alloy)

Brass is an alloy of metal that is copper and zinc. Hence, the metallic bonding is present in the brass.

Rubber

It is a polymer whose monomer unit is isoprene, which is a covalent compound. The isoprene units are attached in repeated units to form rubber by covalent bonding.

Barium sulfide ( $BaS$ )

Due to the large electronegativity difference between barium and sulfur, barium sulfide is an ionic compound. Thus, ionic bonding is present in barium sulfide.

Solid xenon

Only xenon atoms are present in solid xenon which are interacted by weak Van der Waal's interactions.

Bronze

Bronze is an alloy of metal that is copper and tin. Hence, the metallic bonding is present in the brass.

Nylon

It is a polymer whose monomer unit is caprolactam, which is a covalent compound. The caprolactam units are attached in repeated units to form nylon by covalent bonding.

Aluminum phosphide ( $AlP$ )

Aluminum phosphide is a covalent compound and thus involves covalent bonding.

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2 years ago

. -9 + 6 - (-2) Answers?

Kaylis [27]

The answer is -1. 2 subtraction signs next to each other for an addition sign

5 0

2 years ago

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