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3 years ago

How to remember first 20 periodic table

Chemistry

1 answer:

Sergeeva-Olga [200]3 years ago

4 0

Answer:

The first 20 Elements of the Periodic Table: Hydrogen, Helium, Lithium, Beryllium, Boron, Carbon, Nitrogen, Oxygen, Fluorine, Neon, Sodium, Magnesium, Aluminium, Silicon, Phosphorus, Sulphur, Chlorine, Argon, Potassium, Calcium.

Mnemonic:

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Mnemonic:

He Has Light Brain But Can Not Offer Full Nine Subjects, May All Senior Professional Scientists Come And Protect Chemistry

Mnemonic:

He Has Large Brain But Can Not Offer Full Nine Subjects, Master Art Students Prefer Simple Colours And Pretty Colours

Mnemonic:

"H.HeLi, B.BCNOF and NeNa MgAl SiPS ClArKCa"

Mnemonic:

"Hi Helen, Listen B.B.C. News On Friday N(e)ight. Naughty Maggie Always Sings Pop Songs. Clever Archie Kissed Cathy."

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5. A hollow glass sphere has a volume of 350 mL and

Rina8888 [55]

Explanation:

Given that,

Volume of a hallow glass sphere is 350 mL

Specific gravity is 1.252

We need to find the weight of the sphere. The ratio of density of substance to the density of water is called specific gravity.

The density of water is 1 g/mL

$\text{specific gravity}=\dfrac{\text{density of substance}}{\text{density of water}}\\\\SG=\dfrac{m}{V\times \rho_w}\\\\m=SG\times V\times \rho_w\\\\m=1.252\times 350\ mL\times 1\ g/mL\\\\m=438.2\ \text{grams}$

We know that,

1 pound = 453.592 grams

So,

m = 0.97 lbs

So, the weight of the sphere is 0.97 lbs or 0.97 pounds.

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4 years ago

How maby electrons fill an orbit

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Each can hold two electrons

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4 years ago

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What type of molecular model shows all the atoms and bonds in an organic molecule

ValentinkaMS [17]

Answer:

Structural formula shows the atoms and bondsin an organic compound.

Explanation:

Structural formula of methane shows

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3 years ago

(A) H2SeO4(aq) + 2 Cl-(aq) + 2 H+(aq) → H2SeO3(aq) + Cl2(g) + H2O(l) (B) S8(s) + 8 O2(g) → 8 SO2(g) (C) 3 Br2(aq) + 6 OH-(aq) →

AVprozaik [17]

Answer:

Explanation:

Oxidation occurs when the Nox number increases and a reduction occurs when the Nox number decreases. So, let's verify in which reaction the same reactant has elements that both occur after the reaction.

A) H₂SeO₄: H = +1, O = -2 (fixed)

Se: x +2*1 + 4*(-2) = 0

x + 2 - 8= 0

x = +6

Cl⁻: -1 (ions have Nox equal to its charge)

H⁺: +1

H₂SeO₃: H = + 1, O = -2

Se: x +2*1 + 3*(-2) = 0

x + 2 -6 = 0

x = + 4 (Se reduces)

Cl₂: Cl = 0 (simple molecule, so Cl oxides)

H₂O: H = +1, O = -2

B) S₈: S = 0

O₂: O = 0

SO₂: O = -2, S: x + 2*(-2) = 0 -> x = +4 (S oxides and O reduces)

C) Br₂: Br = 0

OH⁻ : O = -2, H = +1

Br⁻ = -1 (Br reduces)

BrO₃⁻: O = -2, Br: x +3x(-2) = -1 -> x = +5 (Br oxides)

H₂O: H = +1, O = -2

D) Ca²⁺: Ca = +2

SO₄²⁻: O = -2, S: x +4*(-2) = -2 -> x = +6

CaSO₄: O = -2, S = +6, Ca = +2

E) PtCl₄: Cl = -1 (fixed), Pt: x + 4*(-1) = 0 -> x = +4

Cl⁻: Cl = -1

PtCl₆²⁻: Cl = -1, Pt = x + 6*(-1) = -2 -> x = +4

So, only in letter C Br₂ is undergoes both oxidation and reduction.

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3 years ago

The chemical _____________ is commonly used in "cold sterilization" trays to sterilize hand instruments. It can be harmful to ot

Law Incorporation [45]

The chemical is Glutaraldehyde

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3 years ago

How to remember first 20 periodic table​

How to remember first 20 periodic table