The visible constellations<span> are definitely different
between the Northern and Southern Hemispheres. In general, at any given point
on Earth, only around 50% of the sky will be visible. We can understand this by
considering the atmosphere as a sphere around the earth. The sky any person can
view at one point can be compared to a giant dome equal to half of the sphere.
And because the Earth rotates, the dome we can see changes, unless one is
sitting directly on the North or South Pole.</span>
A radioactive tracer, I believe. Someone check that lol.
Answer:
Anion Gained 3 18
Cation Lost 2 36
Cation Lost 3 23
Explanation:
Looking at the ionic notation, the negative symbol (-) indicates that there are more electrons than protons and the positive symbol (+) indicates that there are more protons than electrons.
The number tells you how many was gained or lost.
To determine how many electrons are left, you base this off how many protons there are. The number of protons in an atom is expressed by the atomic number. In a stable atom, you have an equal number of protons and electrons.
Ions occur when electrons are gained or lost.
A cation is positively charged because it LOST an electron. Since there are more protons than electrons, the charge would be positive.
An anion is negatively charged because it gained an electron. Since there are more electrons than protons, the charge would be negative.
Using the explanation above, you can see how the answers were obtained. As for the last column, just use basic math to do this.
The atomic number of Phosphorus (P) is 15, so this means that there are 15 protons. Since it gained 3 electrons, just add 3 to 15:
15 + 3 = 18
Sr has an atomic number 38. Since it lost 2 electrons, just subtract 2 from the atomic number.
38-2 = 36
Fe has an atomic number 26. It lost 3 electrons, so we subtract again.
26-3 = 23
The mass of 2.47 moles of fluorine atom is 46.9 g
calculation
mass of Fluorine= moles x molar mass
moles = 2.47 moles
molar mass of fluorine = 18.998 g/mol
mass is therefore= 2.47 moles x 18.008 g/mol = 46.9 g