pls help i have to pick 3 T-T​

Answer:

[Kr] 4d² 5s² option b will be correct answer

B. intermolecular attractions.

Answer:

The half-life of Th-232 is 1.4 ∙ 10¹⁰ years.

Explanation:

helium

Helium gas is not found in earth crust

Answer:

D. gain one electron

Explanation:

In order to become a chemically stable ion, a neutral atom of sodium will gain one electron. Therefore, the correct option is option D.

Chemical stability in chemistry refers to a chemical system's thermodynamic stability. When a system reaches its lowest energy state or in thermodynamic equilibrium with its surroundings, thermodynamic stability occurs.

It could be a spontaneous process when the total number of atoms or molecules in a given shape is conserved despite the fact that individual particles or atoms change forms. In order to become a chemically stable ion, a neutral atom of sodium will gain one electron.

Therefore, the correct option is option D.

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The description of the molecules shown is it is unsaturated alkynes. The correct option is A.

Alkynes are unsaturated double bond containing compound that react with hydrogen when a catalyst is present.

The pie bond shows that the hydrogen atoms are lost from the alkanes.

Thus, the correct option is A, unsaturated alkynes.

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Answer:

Invertebrates are animals which do not have vertibral column. They do not debelop it also. For example: Arthropods , Crawfish and Sea Urchin.

Answer:

I believe it's radiation, but please correct me if I'm wrong.

Explanation: Have a good day !

Answer:

1) A. NO

2) B. 4

3) D. 8

Explanation:

Answer:

Gravity, or gravitation, is a natural phenomenon by which all things with mass or energy—including planets, stars, galaxies, and even light—are brought toward one another. On Earth, gravity gives weight to physical objects, and the Moon's gravity causes the ocean tides.

Gravity, also called gravitation, in mechanics, the universal force of attraction acting between all matter. ... On Earth all bodies have a weight, or downward force of gravity, proportional to their mass, which Earth's mass exerts on them. Gravity is measured by the acceleration that it gives to freely falling objects

The gravitational force is a force that attracts any two objects with mass. We call the gravitational force attractive because it always tries to pull masses together, it never pushes them apart. In fact, every object, including you, is pulling on every other object in the entire universe!

Gravitational force is the force that attracts to objects with mass. ... This forces tries to pull masses together, that is why attractive in nature. For example: When ball is thrown upwards it always come downwards after a certain height because the ball is pulled or attracted by the Earth's gravitation la force.

¯\_(ツ)_/¯

Answer:

Good Question!!! No one has found the answer to that question.

Explanation:

Answer:

b) ions

Explanation:

Answer: all of the above

Explanation:

Answer:

radio waves

Explanation:

which has the longest wavelength and lowest frequency and energy. Ultraviolet light (UV) is divided into three regions: UV A, wavelength = 400 - 320 nm UV B, wavelength = 320 - 280 nm

Answer:

Aerobic Respiration

It can be found in the cytoplasm and the mitochondria.

Glucose breaks down into carbon dioxide and water.

Anaerobic Respiration

It can be found only in the cytoplasmic.

Glucose breaks down into ethyl alcohol, carbon dioxide and energy

Answer:

calcium hydroxide.............

The Alkaline earth metal present in the following materials like lime stone , slaked lime , quicklime and gypsum is Calcium and the Alkaline earth metal present in Epsom salt is Magnesium.

The alkaline earth metals are those elements that correspond to group 2 in the modern periodic table which includes beryllium, magnesium, calcium, strontium, barium, and radium. The elements in this group are quite similar in their physical and chemical properties.

For above information, Calcium is the [tex]20^t^h[/tex]element and Magnesium is the [tex]12^t^h[/tex] element in the periodic table.

Chemically, the given materials which are mentioned above is represented in following manner.

Limestone is Calcium Carbonate -[tex]CaCO_3[/tex]

Slaked Lime is Calcium Hydroxide - [tex]Ca(OH)_2[/tex]

Quicklime is Calcium Oxide - CaO

Gypsum is Calcium Sulfate Dihydrate - [tex]CaSO_4.2H_2O[/tex]

Epsom salt is Magnesium Sulfate - [tex]MgSO_4[/tex]

Thus, the Alkaline earth metal present in the following materials like lime stone , slaked lime , quicklime and gypsum is Calcium and the Alkaline earth metal present in Epsom salt is Magnesium.

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The above question is incomplete. Completed question is Which alkaline earth metal is the components of the following. Materials lime stone , slaked lime , quick lime , gypsum , Epsom salt.

Answer:

A. He sent a cathode ray between electrically charged metal plates

Answer:

A

Explanation:

Answer:

he charge on an electron is -1. Explanation : Electron is a subatomic particle whose symbol is . The electrical charge on an electron is negative. The electron was discovered by the J.J. Thomson. The mass of an electron is . The charge on electron and proton is equal but opposite. Neutron has zero charge and proton has +1 charge.

Explanation:

Answer:

[tex]q=8\times 10^{-19}\ C[/tex]

Explanation:

Given that,

The charge of a single proton is [tex]1.6\times 10^{-19}\ C[/tex]

There are 5 protons in the nucleus. The nuclear charge of an atom of boron is given by :

[tex]q=5\times 1.6\times 10^{-19}\\\\q=8\times 10^{-19}\ C[/tex]

So, the required charge is [tex]8\times 10^{-19}\ C[/tex].

Answer:

It isn't only for the eating habits but also for building nests, hunting small insects, birds, other creatures including defence. Birds have a narrow small throat so the beak helps ripping off small peices of a big animal l(small bird) and for insects they crush and swallow it, they se their beak for feeding their children by grinding food in their beak and transferring it to the youngsters mouth

Answer:

2.6299

its easy

Answer:

D: It combines with oxygen to form a gas.

Explanation:

Carbon is classified as an element because of its ability to combine with other elements and form a new substance or compound.

Looking at the options, the correct option in the light is option D

Answer:

Reactants have more energy than products

Explanation:

Generally, in an exothermic reaction heat is released. In other words, energy is released. So you start with reactants which have a set amount of stored chemical energy, and you lose some in the reaction. Since energy is 'leaving', the stored chemical energy in the products is less than what we started with in the reactants. When given a graph, you can tell this is true because going from left to right, the line representing the stored chemical energy will start at a higher level than where it ends.

The true statement about an exothermic reaction is that reactants have more energy than products.

An exothermic reaction is one in which the energy of reactants is greater than that of products. As such, energy is given off during the reaction in form of heat.

Thus, the true statement about an exothermic reaction is that reactants have more energy than products.

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Answer:

Oganesson!

It is a synthetic chemical element with the symbol Og and atomic number 118. It was first synthesized in 2002 at the Joint Institute for Nuclear Research in Dubna, near Moscow, Russia, by a joint team of Russian and American scientists.

Answer:

the last element is ogasnesson