The two are potassium and rubidium. Why? Na is an alkali metal. As you go down the metals become more reactive.
Calcium has 20 protons. Why? The atomic # is 20 (the one at the top).
It has 20 neutrons. Why? The atomic mass (the number on the bottom) is ~40, ignoring electron mass. 40- 20 protons = 20 neutrons.
It has 20 electrons.
Why? The # of protons and electrons is the same. Ions aren't on the periodic table.
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dominant trait is opposed to a recessive trait which is expressed only when two copies of the gene are present.
Summer
, for the northern hemisphere, summer is the warmest time of year. It's not because the planet is that much closer to the Sun, it's because the top part of the Earth is facing the Sun for a amount of time.
The Sun is directly over the Equator during the autumnal equinox, and heating the northern and southern hemispheres equally. As the northern hemisphere is moving towards shorter days and the cold winter, the southern hemisphere is watching the snows melt and the flowers bloom during their spring.
Summer is the season where the Earth is tilted way from the Sun and the South Pole is getting all of the light
Spring is a bit of a mirror image to our position in autumn. The Sun is directly over the Equator during the equinox and the northern and southern hemispheres
Answer:
Calcium is a silvery-white, soft metal that tarnishes rapidly in air and reacts with water. Calcium metal is used as a reducing agent in preparing other metals such as thorium and uranium. It is also used as an alloying agent for aluminium, beryllium, copper, lead and magnesium alloys. Calcium is essential to all living things, particularly for the growth of healthy teeth and bones. Calcium phosphate is the main component of bone. The average human contains about 1 kilogram of calcium.
Explanation:
