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:
cesium
Explanation: because it says so online I have no idea what you are talking about so I guess google is correct
To measure the density of the stone placed in a graduated cylinder let us follow these steps bellow
- Measure the volume of water poured into a graduated cylinder
- Place the object in the water and remeasure the volume.
- The difference between the two volume measurements is the volume of the object.
- Divide the mass by the volume to calculate the density of the object.
<em>We know that the formula for density is given as </em>
Given data
Mass = 8gram
Initial Volume of water in cylinder = 25mL
Final Volume of water in cylinder = 29mL
Hence the volume of the rock = 29-25 = 4mL
Therefore the density of the rock = 8/4 = 2 g/mL
Learn more:
brainly.com/question/17336041
Answer:
Number of moles of solute = 0.6 mole
Mass =13.8 g
Explanation:
Given data:
Number of moles of sodium = ?
Volume = 2.0 L
Molarity = 0.30 M
Mass in gram of sodium= ?
Solution:
<em>Number of moles:</em>
Molarity = number of moles of solute / volume in litter
Number of moles of solute = Molarity × volume in litter
Number of moles of solute = 0.30 M × 2.0 L
Number of moles of solute = 0.6 mole
<em>Mass in gram:</em>
Mass = Number of moles × molar mass
Mass = 0.6 mole× 23 g/mol
Mass =13.8 g
