Final answer:
The isoelectronic species to Br+ are Se and As-, as they both have the same number of electrons (34) as Br+. The other listed atoms and ions do not share this number of electrons and thus are not isoelectronic with Br+.
Step-by-step explanation:
To determine which atom or ion is isoelectronic with Br+, we must first understand the term 'isoelectronic.' This refers to atoms or ions that have the same number of electrons. The Br+ ion has one less electron than the neutral bromine atom, which has an atomic number of 35 (the number of protons and therefore the number of electrons in a neutral atom). Therefore, the Br+ ion has 34 electrons.
To find isoelectronic species, we look for those with the same number of electrons. Selenium (Se) has an atomic number of 34, so the neutral Se atom has 34 electrons. Arsenic (As) has an atomic number of 33, so As−, with one extra electron, would also have 34 electrons. Krypton (Kr), the noble gas, has an atomic number of 36, so it too has 36 electrons. Gallium (Ga) has an atomic number of 31, and losing three electrons to form Ga3+ would leave it with 28 electrons, not isoelectronic with Br+. Finally, Chlorine (Cl) has 17 protons; gaining one electron to form Cl− gives it 18 electrons, which is not the same as Br+.
The correct answer would be Se and As−, so option (d) is incorrect. Options (a), (b), and (c) are incorrect because they include species that are not isoelectronic with Br+. The correct answer is not provided amongst the options. However, both Se and As− are isoelectronic with Br+.