Answer:
b
Explanation:
stable climate will mean there is one climate and we will have the same animals and plants everywere
Dmitri Mendeleev was the first to publish the classification.
Answer:
The sum of first 30 terms of the arithmetic progression is <u>2160.</u>
Explanation:
For an arithmetic progression, the sum of first 
terms with first term as 
and common difference 
is given as:
Now, it is given that:
Now, plug in these values and frame two equations in 
Now, we solve equations (1) and (2) for . Subtract equation (1) from equation (2). This gives,
Now, plug in the value of 
in equation (1) and solve for .
Plug in the values of 
in the sum formula to find the sum of first 30 terms.
Now, the sum of first 30 terms is given as:
Therefore, the sum of first 30 terms of the arithmetic progression is 2160.
Answer:
The element iodine forms an anion with the charge -1. The symbol for this ion is I⁻¹, and the name is iodide. The number of electrons in this ion is 7.
Explanation:
Hello,
In this case, we have to consider iodine has the capacity to accept the electrons lost by other elements such as metals or hydrogen by becoming negatively charged. Such phenomena makes iodine to form an anion (negatively charged) with the charge -1, since it only needs one electron to attain the octet. Moreover, the symbol of such ion is I⁻¹ and its name is iodide. By cause of the aforementioned, the number of electrons it has is 7 since at its outer shell seven electrons are found (see electron configuration Kr,5s²,5p⁵).
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