All categories

2 years ago

Which statement about the periodic table is true?

Chemistry

1 answer:

dedylja [7]2 years ago

8 0

Answer

Two different elements have similar chemical properties when they have the same number of valence electrons in their outermost energy level. ... Elements in the same column of the Periodic Table have the same number of valence electrons – that's why they have similar chemical properties.

You might be interested in

Which choice correctly places the discovery of subatomic particles in order from earliest to latest?

xeze [42]

Wait hold up do you live in Wilson county????

7 0

3 years ago

Alchemists were medieval scholars and philosophers who were the forerunners of modern-day chemists. many tried repeatedly to tra

AlladinOne [14]

Answer is: because they were using simple chemical reactions to transform elements, but that is possible only with nuclear reactions, which in that time were not possible to conduct.

Nuclear reactions can produce new elements, because number of protons and neutrons is changed, lead and gold have different atomic and mass numbers.

The electrons of an atom participates in a chemical reaction, chemical reactions involve the rearrangement of electrons, because there is transfer, loss, gain and sharing of electrons in chemical reactions, new elements are not formed.

8 0

3 years ago

Must show units and how they cancelli 1.) 175 km to um 3.) 385 nm to dm 5.) 492 um tom 7.) 52 x 103 dm to mm 9.) 321x 1035 mm to

morpeh [17]

Explanation:

1.) 175 km to μm

$1 km=10^9 \mu m$

$175 km=175\times 10^9\mu m=1.75\times 10^{11} \mu m$

3.) 385 nm to dm

$1 nm=10^{-8} dm$

$385 nm=385\times 10^{-8} dm=3.85\times 10^{-6} dm$

5.) 492 μm to m

1 μm = $10^{-6} m$

$492 \μm=492\times 10^{-6} m=4.92\times 10^{-4} m$

7.) $52\times 10^3$ dm to mm

1 dm = 100 mm

$52\times 10^3 dm=52\times 10^3\times 100 mm=5.2\times 10^{6}dm$

9.) $321\times 10^{35}$ mm to km

$1 mm = 10^{-6} km$

$321\times 10^{35} mm=321\times 10^{35}\times 10^{-6} km=3.21\times 10^{31} km$

11.) $456\times 10^3$ m to km

m = 0.001 km

$456\times 10^3m =456\times 10^3 m\times 0.001 km=456 km$

13.) $422\times 10^3$ m to nm

$1 m = 10^{9} nm$

$422\times 10^3 m=422\times 10^3\times 10^{9} nm=4.22\times 10^{14} nm$

15.) $4.87\times 10^{30}$ m to pm

$1 m = 10^{12} pm$

$4.87\times 10^{30} m=4.87\times 10^{30}\times 10^{12} pm=4.82\times 10^{42} pm$

17.) $5.26\times 10^3$ m to um

1 m = $10^{6} \mu m$

$5.26\times 10^3 m=5.26\times 10^3\times 10^6 \mu m=5.26\times 10^{9} \mu m$

19.) $1.25\times 10^{35}$ m to Mm

1 m = $10^{-6} Mm$

$1.25\times 10^{35} m=1.25\times 10^{35}\times 10^{-6} Mm=1.25\times 10^{-29} Mm$

21.) $4.22\times 10^3$ Tm to nm

$1 Tm = 10^{21} nm$

$4.22\times 10^3 Tm=4.22\times 10^3\times 10^{21} nm=4.22\times 10^{24} nm$

6 0

3 years ago

1) A potassium carbonate hydrate has a formula K2CO3.XH2O. 10g of the hydrate leave 7.83g of anhydrous salt upon heating. Deduce

OLEGan [10]

The formula of the hydrated potassium carbonate salt is K₂CO₃.2H₂O

Based on the calculated mass ratio of carbon and oxygen in carbon dioxide, carbon has a fixed composition.

<h3>What are hydrated compounds?</h3>

Hydrated compounds are compounds that contain one or more molecules of water physically combined with a molecule of the compound.

The formula of the hydrated potassium carbonate salt is determined as follows:

Mass of the hydrated sample = 10.0 g

Mass of anhydrous salt = 7.83

mass of water = 10 - 7.83

mass of water = 2.17 g

Molar mass of water = 18.0 g

Molar mass of anhydrous potassium carbonate = 138 g

moles of anhydrous potassium carbonate in sample = 7.83/138

moles of anhydrous potassium carbonate = 0.056 moles

moles of water in the hydrated salt = 2.17/18

moles of water in the hydrated salt = 0.12

Mole ratio of water to anhydrous salt = 0.12/0.056

Mole ratio of water to anhydrous salt = 1 : 2

Formula of hydrated salt = K₂CO₃.2H₂O

The mass ratio of carbon to oxygen in the compounds is given below:

Sample 1:

Mass ratio = 3.62 / (13.26 - 3.62)

Mass ratio = 0.38 : 1

Sample 2:

Mass ratio = 5.91 / (21.66 - 5.91)

Mass ratio = 0.38 : 1

Sample 3:

Mass ratio = 7.07 / (25.91 - 7.07)

Mass ratio = 0.38 : 1

Carbon has a fixed composition.

Learn more about hydrated compounds at: brainly.com/question/11112492

#SPJ1

6 0

1 year ago

What happens when magma cools during the rock cycle

Mumz [18]

Answer:

Si las condiciones para que el magma permanezca líquido no perduran, el magma se enfriará y solidificará en una roca ígnea. Una roca que se enfría en el interior de la Tierra se denomina intrusiva o plutónica y su enfriamiento será muy lento, produciendo una estructura cristalina de granos grueso.

Explanation:

7 0

3 years ago