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Naya [18.7K]
2 years ago
7

Calcium atoms have 20 protons, but tend to form ions with a 2+ charge. How

Chemistry
2 answers:
scoray [572]2 years ago
5 0

Answer: With atomic number 20, calcium atoms have 20 positive protons, and the ion has only 18 electrons, which means the net charge is +2. Calcium ions are essential for muscle contractions, nerve impulses, and bone maintenance.

:

Lemur [1.5K]2 years ago
4 0

Answer:

18 electrons

Explanation:

thats because it loses two to become a cation

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Photosynthesis is a cell process used by various organisms. Which of the following best
Dmitry [639]

Answer:

Carbon dioxide and water are turned into sugar and oxygen

3 0
2 years ago
For what reasons would modern scientists accept dalton's atomic theory but not the idea of an atom proposed by the greek philoso
soldi70 [24.7K]

Solution:

The idea of an atom proposed by the Greek philosophers because:

According to Greek Philosopher, matter is composed of small and indivisible particles called atoms. He introduced atoms as too small to be seen, unchangeable, completely solid without internal structure. He proposed that atoms are of variety of shapes and sizes which is responsible for different types of matter.

But according to Dalton’s atomic theory, chemical elements have atoms, which are identical in weight. The different elements have different atoms of different weight. Atoms can combine in whole-number ratios to form compounds. These observations are already introduced by Greek philosopher, but the idea of atomic weight is introduced by Dalton. He introduced the list of 21 elements with their atomic weights and, he was the first to propose the element’s symbol.

4 0
3 years ago
Which of the following is not a characteristic of a metal?
jolli1 [7]

Answer:

B. Poor conductor.

Explanation:

It cannot be A, as only 1 metal is not solid at room temp.

It cannot be C, as most metals are ductile.

It cannot be D, as most metals are malleable.

This leaves B, which is not true about metals, as a lot are very good conductors.

3 0
1 year ago
A sample of 28 Mg decays initially at a rate of 53500 disintegrations per minute, but the decay rate falls to 10980 disintegrati
prisoha [69]

Answer : The half life of 28-Mg in hours is, 6.94

Explanation :

First we have to calculate the rate constant.

Expression for rate law for first order kinetics is given by:

k=\frac{2.303}{t}\log\frac{a}{a-x}

where,

k = rate constant

t = time passed by the sample = 48.0 hr

a = initial amount of the reactant disintegrate = 53500

a - x = amount left after decay process disintegrate = 53500 - 10980 = 42520

Now put all the given values in above equation, we get

k=\frac{2.303}{48.0}\log\frac{53500}{42520}

k=9.98\times 10^{-2}hr^{-1}

Now we have to calculate the half-life.

k=\frac{0.693}{t_{1/2}}

9.98\times 10^{-2}=\frac{0.693}{t_{1/2}}

t_{1/2}=6.94hr

Therefore, the half life of 28-Mg in hours is, 6.94

8 0
3 years ago
.22
Alja [10]

Answer:its b

Explanation:

7 0
3 years ago
Read 2 more answers
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