Which of these is an isoelectronic series? 1) na+, k+, rb+, cs+ 2) k+, ca2+, or, s2– 3) na+, mg2+, s2–, cl– 4) li, be, b, c 5) n
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An isoelectronic series is where all of the ions listed have the same number of electrons in their atoms. When an atom has net charge of zero or neutral, it has equal number of protons and electrons. Hence, it means that the atomic number = no. of protons = no. of electrons. If these atoms become ions, they gain a net charge of + or -. Positive ions are cations. This means that they readily GIVE UP electrons, whereas negative ions (anions) readily ACCEPT electrons. So, to know which of these are isoelectronic, let's establish first the number of electron in a neutral atom from the periodic table:
Na=11; K=19; Rb=37; Cs = 55; Ca=20; S=16; Mg=12; Li=3; Be=4; B=5; C=6
A. Na⁺: 11-1 = 10 electrons
K⁺: 19 - 1 = 18 electrons
Rb⁺: 37-1 = 36 electrons
B. K⁺: 19 - 1 = 18 electrons
Ca²⁺: 20 - 2 = 18 electrons
S²⁻: 16 +2 = 18 electrons
C. Na⁺: 11-1 = 10 electrons
Mg²⁺: 12 - 2 = 10 electrons
S²⁻: 16 +2 = 18 electrons
D. Li=3 electrons
Be=4 electrons
B=5 electrons
C=6 electrons
The answer is letter B.
Answer:
C. cooler than both the crust and the core
Explanation:
It is observed that at the mantle, temperatures range from estimatedly 200 °C (392 °F) around the upper boundary with the crust to approximately 4,000 °C (7,230 °F) at the core-mantle boundary.
So we can say the mantle is cooler than both the crust and the core.
B
Explanation:
option b is correct because
hydrogen is smallest atom
isotopes of elements have different atomic mass
atom mass have nothing to do with elemental identity
Most solids a) are dense and difficult to compress.
Most solids are closely compacted, their molecules are close together and vibrate. They don't move freely like gas or water molecules do.
They are difficult to be squeezed or flattened.
<u>Answer:</u> The isomers are shown in the image below.
<u>Explanation:</u>
Isomers are defined as the chemical compounds having the same number and kinds of atoms but arrangement are different.
For the alkane having four carbon atoms and 1 bromine atom, the IUPAC name of the haloalkane is bromobutane
There are 4 possible isomers for the given haloalkane compound:
- 1-bromobutane
- 2-bromobutane
- 1-bromo-2-methylpropane
- 2-bromo-2-methylpropane
The isomers of the given organic compound is shown in the image below.
