When a calcium atom loses two electrons, it becomes positively charged because it has more protons than electrons. In this case, since two electrons are lost, the calcium ion has a charge of +2.
When an atom loses or gains electrons, it undergoes a process called ionization, resulting in the formation of an ion. In the case of calcium (Ca), it typically loses two electrons to achieve a more stable electron configuration.
A neutral calcium atom has 20 electrons, with the electronic configuration 1s² 2s² 2p⁶ 3s² 3p⁶ 4s². By losing its two outermost electrons from the 4s orbital, it forms a calcium ion (Ca²⁺) with 18 electrons.
The loss of two negatively charged electrons leaves the calcium ion with a net positive charge. The charge on an ion is indicated by a superscript after the ion symbol. In this case, the superscript is +2, denoting that the calcium ion has a charge of +2.
Hence, the correct answer is +2.
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bronze
air
water
If the substance entering the cell was in higher concentration inside the cell than outside the cell, the type of transport that would be required here is known as Active transport. Thus, the correct option for this question is A.
Active transport may be defined as a type of transport that occurs against the concentration gradient and therefore it is mediated by carrier proteins. In this type of transport, metabolic energy is utilized in order to move ions or molecules against the concentration gradient. It is directly opposite to passive transport.
Active transport results in the accumulation of solute on one side of the membrane. It is different from the carrier proteins mediated facilitated diffusion. This transport decreases the entropy of the reaction.
Therefore, active transport would be required in order to migrate any substance from a lower concentration to a higher concentration. Thus, the correct option for this question is A.
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B. zinc, gold, aluminium, oxygen.
C. nitrogen, copper, mercury, water.
D. Chlorine, argon, sodium, limestone.
A list that contains only element is option B which include zinc, gold, aluminum, and oxygen.
A chemical element may be defined as a type of simple substance that significantly cannot be broken down or fragmented into smaller parts or changed into another substance.
The basic part of an element is an atom, which contains subatomic particles like protons, neutrons, and electrons. All atoms of an element have the same number of protons. In list A, the air is not an element, in list C, water is not an element, in list D, limestone is not an element. While list B includes all elements like zinc, gold, aluminum, and oxygen.
Therefore, a list that contains only elements is option B which includes zinc, gold, aluminum, and oxygen.
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Removing the fuel will stop the fire, this is called a firebreak. Therefore, the fuel part of the fire triangle does firebreak.
The fire triangle can be described as a simple model for understanding the necessary ingredients for most fires. The triangle represents the three elements a fire requires to ignite: heat, fuel, and an oxidizing agent.
A fire naturally takes place when the elements are present and combined in the right mixture. A fire can be stopped or extinguished by removing any one of the elements in the fire triangle.
For example, covering the fire with a blanket blocks the supply of oxygen and can stop a fire. In large fires, decreasing the amount of oxygen is not an option because there is no effective way to make that happen in an extended area.
Fires in forests can be stopped by cutting down trees to make a gap known as a 'fire break'. Because cutting the trees can act as removing fuel.
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