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2 years ago

Elements in group 7A in the periodic table are called the halogens: elements in group 6A are called the chalcogens (a)

Chemistry

1 answer:

Gnom [1K]2 years ago

6 0

Answer:

Most common oxidation state of the chalcogens is -2, most common oxidation state of the halogens is -1.

Explanation:

For atomic radii, the chalcogens have a larger atomic radii than the halogens

This is because atomic radii decreases across the period due to increase in nuclear charge.

For ionic radii the chalcogens also have larger ionic radii than the halogens. This is because the chalcogens always carry a -2 charge compared to halogens that carry a -1 charge. Since -2 is the most common oxidation state for chalcogens and -1 is the most common oxidation state for the halogens.

In terms of oxidation states, the halogens show a higher value of common oxidation state -1 while for chalcogens is -2 even though +2, +4 and +6 oxidation states are also well known.

First ionization energy of halogens is greater than that of the chalcogens due to greater effective nuclear charge.

The second ionization energy of chalcogens is greater than that of the halogens.

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2 years ago

Oh no! Igor stepped on a piece of glass on the sidewalk in front of

Helen [10]

Answer: The correct sequence for the series of event would be.

1. Igor's toe is being cut by the glass.

2. The wound surrounding the injury becomes infected with bacteria from Igor's foot.

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5. The complex becomes trapped in a lymph node and is engulfed by a phagocyte.

6. The bacteria is destroyed.

Explanation:

Whenever there is any cut or wound in the body and body encounters invasion of the foreign materials it considers it as harmful pathogen.

These pathogens when enters the body it is considered as antigen, it then travels to the lymphatic system.

These bacterial complex is then killed by the phagocytes and digested by the body.

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2 years ago

g A solution contains 100mM NaCl, 20mM CaCl2, and 20mM urea. We would say this solution is __________ compared to a 300 mOsM sol

ICE Princess25 [194]

Answer:

A solution contains 100mM NaCl, 20mM CaCl2, and 20mM urea. We would say this solution is hypotonic compared to a 300 mOsM solution and hypotonic compared to a cell with 300 mOsM (non-penetrating solutes) interior.

Explanation:

The osmolarity is calculated from the molar concentration of the active particles in the solution. We have a solution that is composed of NaCl, CaCl₂ and urea.

When they are dissolved in water, they dissociate into particles as follows:

NaCl → Na⁺ + Cl⁻ (2 particles per compound)

CaCl₂ → Ca²⁺ + 2 Cl⁻ (3 particles per compound)

urea: not dissociation (1 particle per compound)

Then, we have to calculate the osmolarity of the solution. We multiply the molarity of each compound by the number of particles produced by the compound in water:

Osm = (100 mM NaCl x 2) + (20 mM CaCl₂ x 3) + (20 mM urea x 1) = 280 mOsm

Compared with 300 mOsm, 280 mOsm has a lower osmolarity, so it is a hypotonic solution.

To compare with a cell's osmolarity, we have to consider only the non-penetrating solutes. Urea is considered a penetrating solute for mammalian cells. So, the osmolarity of non-penetrating solutes (NaCl and CaCl₂) is calculated as:

Osm (non-penetrating solutes) = (100 mM NaCl x 2) + (20 mM CaCl₂ x 3) = 260 mOsm

Therefore, we have:

Compared to 300 mOsm solution ⇒ 280 mOsm solution is a hypotonic solution

Compared to a cell with 300 mOsm ⇒ 260 mOsm solution is hypotonic

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2 years ago

Tips for studying last minute (respiratory system)?? most helpful tips will be rewarded brainliest

Aleks [24]

Tips
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- watch YouTube clips on the respiratory system

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2 years ago