Answer: An atom that has gained an electron.
Explanation:
The number of protons in an atom cannot change except for some exceptional circumstances.
Cations (or metal ions) are formed when atoms lose electrons, as they want to form a complete outer electron shell to become as stable as possible.
For example, potassium is a 1+ ion, because it has one electron in its outer shell (and in group one). Therefore, to become more stable that electron is lost to become an ion or cation. As one electron is lost, the potassium cation charge is 1+ as the charge of an electron is 1-.
Answer:
Atomic models are important because, they help us visualize the interior of atoms and molecules, and thereby predicting properties of matter.
Explanation:
We study the various atomic models in our course of study because, it is important for us to know, how did people come to the present concept of an atom. How did physics evolve from classical to quantum physics.
All these are important for us to know and thus, knowledge about various atomic models, their discoveries and drawbacks and finally improvements based on scientific evidence present at that time is important for us to understand the underlying theory very well.
The substances Oxygen and Hydrogen are elements.
Answer:

Explanation:
Hello,
In this case, considering the density and mass of both water and heptane we first compute the volume of each one:

Now, the total volume is:

Which is equal to:

Then, by knowing that the volume of a cylinder is πr²h or π(D/2)²h, we solve for the height as follows:

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